1. 打破误区：为什么有人6小时睡眠就够？
1.1 睡眠需求的个体差异：从“8小时标准”到“个性化睡眠”
你是不是也经常听到“每天睡够8小时才健康”的说法？这句话听起来很有道理，但它可能只是一个“通用模板”，并不适用于每个人。实际上，我们对睡眠的需求就像指纹一样，每个人都有自己独特的“睡眠密码”。有的人天生就是“短睡眠者”，即便只睡6小时，也能精神抖擞，而有的人则需要更长的睡眠时间才能恢复元气。
这种个体差异，很大程度上是由我们的“基因”决定的 1。科学家们通过研究发现，一些特定的基因变异，比如NR3A基因 2，都可能让人天生拥有较短的睡眠需求，却不影响他们的健康。这些“天选之人”可能每天只睡4-6小时，却能保持旺盛的精力。有研究甚至在果蝇身上进行了“选育”，发现经过13代选择后，有的果蝇夜间睡眠时间能缩短到3.3小时，而且寿命并没有受到影响 3。这就像身体里安装了一个高效的“快充模式”，在更短的时间内完成充电。
除了基因，年龄和生活习惯也会影响我们的睡眠需求。小孩子和青少年通常需要更多的睡眠来支持大脑学习 45，而成年人，尤其是老年人，睡眠结构会发生变化，可能夜间睡眠时间会相对缩短，但如果睡眠质量好，同样可以保持健康。
所以，与其盲目追求“8小时标准”，不如把注意力放在“个性化睡眠”上。我们需要倾听自己身体的声音，找到最适合自己的睡眠时长。而判断自己睡眠是否充足的关键，往往不在于你睡了多久，而在于你醒来后的感受：是否感到清醒、精力充沛，而不是昏昏沉沉、疲惫不堪。研究也表明，睡眠的“质量”远比单纯的“时长”更关键 6。如果6小时的睡眠是高质量的，它可能比10小时的低质量睡眠更能让你恢复元气。
1.2 睡眠周期的秘密：6小时如何等于8小时的深度修复
既然不是所有人都得睡足8小时，那么这6小时的睡眠，要怎样才能达到“高效充电”的效果呢？这就不得不提到我们睡眠的“运行模式”——睡眠周期了。
我们的睡眠可不是一觉到天亮那么简单，它是一个有规律的循环过程，就像一部精密的机器，分成不同的工作阶段，每个阶段都有自己独特的任务。这个周期一般持续90分钟左右，一夜之间会重复4到6次。主要可以分为两大类：非快速眼动睡眠（NREM）和快速眼动睡眠（REM） 78。
- 非快速眼动睡眠（NREM）：这个阶段又可以细分为三个小阶段：
- N1（浅睡期）：这是你刚入睡的时候，身体和大脑开始放松，但很容易被外界吵醒，就像给机器预热。
- N2（轻度睡眠期）：身体进一步放松，心率和体温下降，大脑活动也逐渐减慢。虽然比N1深一点，但依然是比较浅的睡眠。
- N3（深睡期，也叫慢波睡眠）：这是睡眠中最“硬核”的修复阶段！大脑会释放慢波，身体进入深度休息状态。肌肉完全放松，生长激素大量分泌，免疫系统开始“加班”，身体的细胞和组织在这个时候进行大修和再生。更重要的是，深睡对身体的恢复、精力的充沛和记忆的巩固至关重要 7。可以说，没有足够的深睡，就算睡了10小时也可能感觉没睡一样。
- 快速眼动睡眠（REM）：这个阶段的名字很有趣，因为我们的眼球会在眼皮底下快速转动 910。此时，大脑活动会变得非常活跃，甚至和清醒时差不多，我们大部分的梦境都发生在这个阶段。REM睡眠对情绪调节、学习、记忆整合，特别是处理情绪记忆和巩固学习到的新技能，有着不可替代的作用 7111213。
想象一下，这90分钟的睡眠周期就像一个完整的“充电流程”。从浅睡开始，逐步进入深度睡眠进行身体维护，再到REM睡眠进行大脑的“文件整理”和“情绪备份”。如果你能高效地完成这些流程，即使是6小时，也能帮你完成大约4个完整的睡眠周期。这意味着你的身体和大脑都得到了足够的深度修复和信息处理，就像用“快充模式”给手机充满了电。
相反，那些看起来睡了很久，比如10小时，却依然感到疲惫的人，很可能就是因为他们的睡眠周期被打乱了 14，或者深睡和REM睡眠的比例不够 15。比如，频繁夜醒、睡眠环境嘈杂、睡前玩手机等行为，都可能让你的睡眠停留在浅睡阶段，无法有效地进入深度修复区。这样的“伪休息”就像手机充电时总是断断续续，电量虽然显示得多，但实际能用的却很少，自然就无法让你一整天都精力充沛了。
所以，关键不在于你躺在床上的时间有多长，而在于这期间你的身体和大脑是否真正进入了高效的“维修”和“整理”状态。高质量的6小时睡眠，能让你在醒来时真正感受到“充满电”的感觉，而这，才是我们追求“精力充沛”的终极目标。
2. 短睡眠的风险预警：哪些行为会让6小时变成“消耗战”
2.1 代谢与认知：短睡眠如何悄悄拖垮身体
前面我们提到，少数“天选之子”即使只睡6小时也能精力充沛。但对于大多数人来说，如果长期睡眠时间少于6小时，可就不是什么好事了。这就像是在透支身体的“银行账户”，短时间内可能感觉不到，但时间一长，各种健康问题就会悄悄找上门来，把你的6小时睡眠变成一场疲惫不堪的“消耗战”。这种长期睡眠不足，在医学上我们称之为“睡眠剥夺” 16。
你可能会问，不就是少睡一两个小时吗？身体还能感受到什么？答案是：当然能！你的身体远比你想象的更精密、更敏感。长期睡眠不足，首先受到冲击的就是我们的新陈代谢系统。
想象一下，你的身体内部有一个精密的化工厂，睡眠就像这个化工厂的“检修时间”。如果检修时间不够，化工厂的生产就会出问题。比如，长期睡眠少于6小时，会增加胰岛素抵抗的风险 171819。这又是什么意思呢？胰岛素就像一把钥匙，能打开细胞的大门，让血液中的糖分（能量）进入细胞。当胰岛素抵抗发生时，这把钥匙就“不好使了”，细胞大门对胰岛素的反应变得迟钝，导致血糖无法顺利进入细胞，只能在血液里越积越多，从而增加患2型糖尿病的风险 1720。
不光如此，睡眠不足还会影响我们身体里的“饥饱信号” 2122。有两种重要的激素：瘦素（Leptin）和饥饿素（Ghrelin）。瘦素是告诉大脑“我饱了”的信号，而饥饿素是告诉大脑“我饿了”的信号。研究发现，睡眠不足会导致瘦素水平下降、饥饿素水平上升 2223。结果就是，你更容易感到饥饿，食欲大增，对高热量食物的渴望也更强烈 1721。长期下来，这就成了肥胖的“助推器” 182425。
除了身体的“化工厂”会出问题，我们的大脑这个“司令部”也会受到严重影响。长期睡眠不足，会悄悄地“腐蚀”你的认知功能。
最令人担忧的是，睡眠不足与阿尔茨海默病（老年痴呆症）之间存在着关联 262728。我们大脑在清醒时会产生一种叫做β淀粉样蛋白（Aβ蛋白）的“垃圾”。睡眠的一个重要功能，就是清除这些大脑垃圾。特别是深度睡眠时，大脑的淋巴系统会变得活跃，帮助清除Aβ蛋白 28。如果长期睡眠不足，阿尔茨海默病的发病风险会显著增加 262728。有研究显示，长期睡眠不足（少于6小时）与阿尔茨海默病的发病风险增加显著相关 2627。
而且，睡眠不足还会让我们的记忆力、注意力和决策能力“掉线”。你可能会发现自己变得健忘、注意力不集中、反应迟钝，甚至做一些简单的判断都会犯错。一项研究显示，持续14天每晚只睡4小时或6小时，会导致认知功能出现累积性的、剂量依赖性的下降，其影响甚至相当于两天完全不睡觉！ 29 更可怕的是，实验参与者往往没有意识到自己认知能力下降了，还以为自己表现得不错，这就像是温水煮青蛙，等到发现时，可能已经付出了很大的代价 29。此外，睡眠不足还会让人对疼痛的感知更加敏感 30。
所以，这里我们强调的“有效6小时”睡眠，是建立在身体各项机能都能正常运转，能够得到充分修复的基础上的。而“被迫6小时”睡眠，则是身体长期处于缺觉状态，不断地在消耗自身的储备，最终导致代谢紊乱、认知下降，甚至增加多种慢性疾病的风险。对于普通人来说，追求“高效6小时”的前提，是确保你的身体能够适应这种模式，而不是通过牺牲健康来换取所谓的“短睡眠”。
2.2 常见误区：这些行为会让短睡眠雪上加霜
既然我们知道了“有效6小时”和“被迫6小时”的巨大差异，那么日常生活中，究竟是哪些“不良习惯”在悄悄地把你的有效睡眠时间变成“被迫消耗”，让本来就不长的6小时雪上加霜呢？
让我们一起看看那些最常见的“睡眠杀手”：
睡前刷手机、玩平板——蓝光的“甜蜜陷阱”
睡前忍不住拿起手机刷刷视频、看看新闻，似乎已经成了很多人的“睡前仪式”。然而，这个习惯对睡眠的破坏力远超你的想象。你的手机、平板屏幕，包括电脑屏幕，会发出大量的蓝光。这种蓝光，可不是什么善茬。它会强烈地抑制我们大脑分泌褪黑素。
褪黑素，你可以把它想象成身体里的“睡眠信号兵”，它告诉你的大脑和身体：“夜深了，该睡觉了。”当蓝光抑制了褪黑素的分泌，就等于你的大脑收不到这个重要的“睡眠信号”，自然就难以入睡，或者入睡时间大大延长 313233。即使你最后睡着了，睡眠质量也会大打折扣，深度睡眠和快速眼动睡眠的时间都可能减少 31。有些研究甚至发现，即使开启了手机的“夜间模式”或使用了所谓的“蓝光过滤应用”，其对改善睡眠质量的效果也并不明显，甚至存在争议 3435。所以，睡前刷手机，就像是在给你的“睡眠信号兵”下达了“原地待命，不许发信号”的指令，结果就是，你的6小时睡眠，很可能大部分时间都浪费在了浅睡和辗转反侧上。
夜宵——肠胃的“加班警报”
忙碌了一天，晚上肚子咕咕叫，来顿丰盛的夜宵犒劳自己？这无疑也是在给你的睡眠“挖坑”。当我们吃东西时，消化系统就开始忙碌起来，胃肠道需要大量能量来分解食物。如果在临睡前吃夜宵，特别是油腻、辛辣的食物，你的消化系统就不得不“加班加点”地工作，这会让你在应该放松休息的时候，身体却还在高速运转。这种不合时宜的进食，不仅会干扰身体的正常昼夜节律，还可能导致胃部不适，甚至胃酸反流，让你辗转反侧，难以进入深度睡眠 36。结果就是，你虽然睡了6小时，但身体却没能得到应有的休息和修复。
“酒精助眠”——饮鸩止渴的假象
有些人可能会觉得，喝点酒有助于入睡，甚至把它当成一种“助眠”手段。一开始，酒精确实会让你感到困倦，似乎能更快地进入睡眠。然而，这只是一种短暂的假象，酒精对睡眠结构有着严重的破坏作用，简直是“饮鸩止渴”！
酒精虽然能缩短入睡时间，但它会显著地破坏你的睡眠周期，尤其是深度睡眠和快速眼动睡眠 3738。你可能会在前半夜睡得昏昏沉沉，但到了后半夜，随着酒精在体内代谢，你更容易醒来，而且醒来后难以再次入睡。研究表明，即使是少量饮酒，也会增加打鼾的风险，从而进一步降低睡眠质量 3839。这样一来，你看似睡了6小时，但实际上得到的都是碎片化、低质量的睡眠，身体和大脑根本无法完成有效的修复工作。
“补觉”——无法弥补的欠债
“平时缺觉没关系，周末多睡一会儿补回来就行了！”如果你也抱有这样的想法，那可就大错特错了。“补觉”这个概念，听起来很美好，但实际上，它很难完全弥补你平时欠下的“睡眠债”。
首先，突如其来的长时间睡眠会打乱你已经建立起来的昼夜节律，让你在周一早上更难清醒，产生所谓的“社会时差”（social jet lag） 36。其次，睡眠的修复作用，更强调的是“及时性”和“持续性”，就像人体细胞的代谢和修复是持续进行的，你不能指望一次性吃顿大餐就能弥补长期营养不良。大脑中一些需要清除的代谢废物，例如前面提到的Aβ蛋白，其清除效率在长期睡眠不足后会显著下降，即使之后补觉，也无法完全恢复到正常水平。
所以，这些常见误区就像一个个“睡眠黑洞”，不断吞噬着你本就有限的睡眠时间，让6小时的睡眠变成了“消耗战”。要真正实现6小时也能精力充沛，首先就要把这些“黑洞”堵上，让你的睡眠效率最大化。
3. 睡眠质量提升：6小时也能“高浓度充电”的核心方法
了解了短睡眠的风险，也排除了那些让睡眠质量打折扣的“坑”，接下来，我们就要进入“实战”阶段了。既然我们追求的是“6小时也能精力充沛”，那么重点就在于如何在这有限的6小时里，实现“高浓度充电”，让每一分钟的睡眠都发挥最大的效用。这就像是给手机配置了最高效的充电器和充电线，在最短的时间内充满电。
实现“高浓度充电”，核心在于提升睡眠质量。我们要从身体的自然规律出发，打造一个最有利于睡眠的环境，并运用科学的方法，让你的身体和大脑主动进入深度修复状态。
3.1 精准入睡：抓住“睡眠窗口”让入睡效率翻倍
想要高效地充电，第一步就是精准地“插上充电器”——也就是高效地入睡。很多人可能都有这样的经历：躺在床上翻来覆去，脑子里像放电影一样停不下来，最后好不容易睡着了，一看时间，已经比计划晚了很久。这不仅缩短了总睡眠时长，还大大降低了睡眠质量。
要做到精准入睡，我们首先要了解身体里两个重要的“指挥官”：昼夜节律和褪黑素。
昼夜节律：身体里的“生物钟”
我们的身体里有一个精密的“生物钟”，它被称为昼夜节律（Circadian Rhythm）40。这个生物钟就像一个无形的指挥家，协调着我们身体内部各种生理活动，包括体温、激素分泌、心率、血压以及睡眠-觉醒周期，让它们在一天24小时内呈现规律性的波动 4142。
昼夜节律最强大的“校准器”就是光照。早晨的阳光会告诉你的生物钟“该起床了”，而夜晚的黑暗则会发出“该睡觉了”的信号。当你的生活作息和昼夜节律保持一致时，身体就会自然而然地在晚上感到困倦，在早上自然醒来。
褪黑素：启动睡眠的“钥匙”
而褪黑素，就是我们生物钟在夜晚发出的“睡眠信号兵” 43。当夜晚降临，环境变暗时，大脑中的松果体就会开始分泌褪黑素，它就像一把开启睡眠的“钥匙”，让你感到困倦，准备入睡。褪黑素的分泌在夜晚达到高峰，然后在天亮时逐渐减少，这与我们的睡眠-觉醒周期紧密相连。
所以，精准入睡的关键，就是顺应你的昼夜节律，并利用好褪黑素的分泌规律。
如何操作？
固定起床时间，反推入睡时间： 这可能是提高睡眠效率最重要的一步！很多人习惯固定入睡时间，但其实，固定起床时间比固定入睡时间更重要。因为起床时间是校准你生物钟最有效的锚点。
- 假设你目标每天睡6小时，那么你先固定一个你必须起床的时间，比如早上7点。那么，你的理想入睡时间就应该反推到凌晨1点。坚持每天7点起床，无论前一晚睡了多久。起初可能有些困难，但几天后，你的身体就会自动在凌晨1点左右感到困倦，这就是你的生物钟被成功校准的信号。
- 这样做的目的，是让你的身体形成稳定的睡眠周期，即使只睡6小时，也能保证你在这6小时内更高效地进入深度睡眠，而不是在床上辗转反侧浪费时间。有规律的作息（包括规律的起床和睡觉时间）与更健康的代谢息息相关 44。
抓住“黄昏困倦期”，让入睡效率翻倍： 在你目标入睡时间前的一到两小时，通常是晚上9点到11点之间，你可能会感受到一阵明显的困意，这被称为“黄昏困倦期”。这是因为你的身体核心温度开始下降，是身体发出的最佳入睡信号 45。如果你能在这个时候上床睡觉，入睡会变得异常轻松和迅速，这就像“顺水推舟”，让入睡效率大大提升。
- 行动建议： 在这个“黄昏困倦期”来临前，就开始做一些放松的事情，比如洗个热水澡、看书、听轻音乐，避免刺激性的活动和电子屏幕。一旦困意袭来，就立刻上床睡觉，不要硬撑。
“体温调节法”：让身体主动进入睡眠模式
你有没有发现，在感到困倦的时候，身体会感到一丝凉意？这可不是错觉，而是你的身体正在为睡眠做准备。体温的下降是启动睡眠的关键生理信号之一 46。我们的身体在入睡前会主动散热，核心体温会随之下降，从而促进睡眠的发生 47。
如何操作？
- 睡前1-2小时泡脚/洗热水澡： 在睡前1-2小时，用40-42℃的热水泡脚或洗个热水澡，持续15-20分钟。这会暂时升高你的体表温度，当身体离开热水后，为了重新达到平衡，会加速向外散热，从而促使你的核心体温快速下降。这种快速的体温下降，会给大脑发出强烈的“该睡觉了”的信号，大大加快你的入睡速度 45。
通过以上方法，你将能够更精准地把握身体的睡眠信号，像给手机找到最佳充电接口一样，让你的6小时睡眠从一开始就进入高效的“充电模式”。
3.2 环境优化：打造“无干扰”睡眠舱的3个细节
想象一下，你正在为手机充电，如果充电口松动、电源不稳，或者周围干扰太多，手机就无法高效充电，甚至会掉电。我们的睡眠也一样！即使你精准地抓住了入睡时机，如果睡眠环境充满“干扰”，你的6小时睡眠也很难达到“高浓度充电”的效果。因此，打造一个“无干扰”的睡眠舱，让卧室成为一个真正放松、助眠的港湾，至关重要。
这里有三个关键细节，帮你把卧室变成你的专属“充电站”：
光线管理：用黑暗拥抱深度睡眠
光线，尤其是夜晚的光线，是影响我们睡眠质量的头号“刺客”。我们前面提过，蓝光会抑制褪黑素分泌。但其实，任何不合时宜的光线，都会干扰你的生物钟，影响睡眠。
- 极致遮光： 卧室的光线越暗越好。安装遮光窗帘是第一步，它可以阻挡窗外路灯、车灯或清晨阳光的侵扰。即使是一丝缝隙透进来的光线，都可能影响你的深度睡眠。
- 睡前用暖光： 临睡前1-2小时，尽量避免使用高亮度的白炽灯或节能灯。把卧室主灯换成柔和的、偏红黄色的暖光台灯。暖光对褪黑素分泌的抑制作用较小，能更好地帮助你进入放松状态，为入睡做好准备 48。
- 杜绝电子设备发光： 手机、平板、电脑、电视，甚至是一些带指示灯的小电器，它们在黑暗中发出的微弱光线，都可能成为影响你睡眠的隐形杀手。睡觉时，最好将这些设备移出卧室，或者用布遮盖住它们的指示灯。
声音隔绝：静谧中的“白噪音魔法”
安静的睡眠环境，是高质量睡眠的基础。但现实生活中，我们很难完全隔绝外界噪音，比如楼上邻居的脚步声、窗外的车鸣声，甚至是伴侣的鼾声。这时候，“白噪音”可能成为你的秘密武器。
- 白噪音的原理： 白噪音（white noise）是一种频率分布均匀的、听起来像“沙沙声”或“电流声”的声音。它之所以能助眠，并不是因为它让你睡着，而是因为它能“掩盖”那些突然的、不规律的噪音，让你的大脑在相对稳定的背景声中更容易放松，减少被吵醒的几率 49。想象一下，如果一个蚊子在你耳边突然“嗡”地一声，你肯定会被吓醒。但如果周围一直有均匀的沙沙声，蚊子的“嗡”声就没那么突兀了。
- 如何使用： 你可以使用白噪音机、专门的白噪音App，或者简单的风扇声（如果声音均匀）来制造白噪音。音量要适中，以不影响听力为原则，并且需在安全声级范围内使用 50。有一些研究表明，白噪音可以缩短入睡时间，并减少夜间觉醒的次数，尤其是在高噪音环境下 51 52。它甚至被应用于新生儿护理和医院环境，帮助改善睡眠 50 53 54 55。
- 选择性隔绝： 如果白噪音让你感到不适，或者你想彻底隔绝噪音，一副舒适的耳塞也是不错的选择。
温度与舒适度：打造你的专属“恒温摇篮”
卧室的温度和床铺的舒适度，直接影响你的身体能否完全放松，进入深度睡眠。
通过细致地调整这些环境细节，你就能为你的6小时睡眠创造一个“高浓度充电”的完美背景。这就像是为你的手机准备了一个专业的充电宝和安静的充电环境，确保在有限的时间内，最大限度地提升充电效率。
4. 饮食与运动：让身体主动“渴望高效睡眠”
想要每天只睡6小时还能精力充沛，光靠改善睡眠环境和掌握入睡技巧还不够。你还需要让身体从内而外地“配合”你，主动地“渴望”高效睡眠。而这一切，都离不开“吃”和“动”这两大关键。我们的身体有一个精密的“生物钟”（昼夜节律），它不仅调控着睡眠，也深深影响着我们的消化、代谢和能量利用 585960。吃得对，动得巧，就能更好地校准你的生物钟，让身体更自然地进入高效睡眠和高效清醒的状态。
4.1 吃对时间与食物：从早餐到晚餐的睡眠友好策略
你吃什么，什么时候吃，都像在给你的身体发送不同的信号。合理的饮食，能帮助稳定血糖、促进睡眠激素分泌，为6小时高效睡眠打下坚实的基础。
早餐：补充蛋白质，稳定血糖，开启活力一天
早餐是一天中最重要的一餐，它就像你身体的“启动键”。吃一顿好的早餐，不仅能为你提供全天的能量，更能稳定你的血糖水平，避免上午出现“犯困”或精力不集中的情况。
- 蛋白质是关键： 早上选择富含蛋白质的食物，比如鸡蛋、牛奶、酸奶、豆浆等。有研究指出，相比低脂早餐，低碳水化合物（通常高蛋白）早餐能更有效地改善血糖控制 61。血糖稳定，你的精神状态自然更佳，能为后续高效的睡眠积累能量。
- 减少高糖碳水： 尽量避免早餐只吃高糖的精制碳水化合物，比如甜面包、糕点、含糖饮料等。它们会迅速升高血糖，然后又迅速回落，导致你很快感到饥饿和疲惫。
午餐：避免过量碳水，告别“饭困”危机
很多人午饭后都会感到一阵阵“饭困”，眼皮打架，恨不得立马趴下睡一觉。这往往和午餐的食物选择有关。
晚餐：选择色氨酸与镁，促进睡眠激素分泌
晚餐的目的是为身体提供营养，同时又要避免给消化系统带来过重负担，影响夜间睡眠。
- 色氨酸的魔法： 选择富含色氨酸的食物，它是我们身体合成血清素和褪黑素的重要原料 6465。血清素是一种“快乐激素”，能让你感到放松和愉悦；而褪黑素，我们前面已经提过，是启动睡眠的“钥匙” 6667。
- 镁的助眠功效： 镁是一种重要的矿物质，它参与了300多种身体酶的反应，对神经和肌肉功能、血糖控制以及血压调节都至关重要。同时，镁也有助于放松肌肉，缓解焦虑，从而促进更好的睡眠 64676869。
- 睡前3小时停食： 这是一个非常重要的习惯！尽量在睡前3小时停止进食。如果睡前吃东西，你的消化系统就不得不在你该休息的时候“加班”，这会干扰身体的修复过程，影响睡眠质量 5870。尤其要避免油腻、辛辣、高糖的食物和咖啡因。如果实在饿，可以喝一小杯温牛奶或吃一根香蕉，它们富含色氨酸，有助于睡眠。
通过合理安排三餐的食物种类和进食时间，你就能更好地调控体内的激素分泌和血糖水平，让你的身体在白天保持旺盛精力，在夜晚则能更顺利地进入高效睡眠模式。
4.2 运动节奏：白天动对了，晚上睡得深
运动不仅能强身健体，更是提升睡眠质量、让你在6小时睡眠后依然精力充沛的“秘密武器”。适当的运动能够调节情绪、缓解压力，最重要的是，它能促进身体内部的平衡，让你在白天更有活力，在晚上睡得更香、更深。研究普遍证实，规律的体育锻炼对改善睡眠质量有显著益处 7172。但关键在于，你要“动对时间”，选择“对的运动”。
有氧运动：晨跑/快走，提升白天精力，告别“瞌睡虫”
无氧运动（力量训练）：需避免睡前，以免“越练越精神”
- 何时进行： 力量训练（如举重、器械训练）对身体的刺激较大，会显著提高心率和体温。建议在下午或傍晚进行，但一定要避免在睡前3小时内进行。
- 工作原理：
傍晚瑜伽/拉伸/太极：缓解压力，调节睡眠激素，为入睡“铺垫”
- 何时进行： 傍晚时分，当你的工作和学习告一段落，是进行一些温和放松运动的最佳时机。
- 工作原理：
- 身心放松： 瑜伽、拉伸、太极这类身心结合的运动，能有效缓解一天的紧张和压力，放松僵硬的肌肉，有助于降低皮质醇（压力激素）水平，促进身体分泌有助于睡眠的激素。
- 改善睡眠质量： 大量研究表明，太极、瑜伽等心身锻炼对改善睡眠质量效果显著，尤其是在老年人、癌症幸存者和更年期女性中 77787980。研究表明，运动，包括有氧运动、抵抗运动、有氧和抵抗运动相结合、身体活动、瑜伽或太极，与睡眠质量的显著改善有关 81。一项研究甚至指出，太极对改善睡眠的效果可能比有氧运动更显著 77。
- 减少夜间不适： 温和的拉伸还能缓解一些可能影响睡眠的身体不适，比如肌肉痉挛。虽然关于拉伸对减少夜间肌肉痉挛的效果仍需更多研究证实，但至少它能帮助放松肌肉 82。此外，像水中运动这样的低冲击性性锻炼，也被发现能有效缓解疼痛并改善睡眠质量，例如对纤维肌痛患者而言 83。
小贴士：
- 规律是关键： 无论选择哪种运动，最重要的是持之以恒，养成规律的运动习惯。身体需要时间来适应和调整。
- 倾听身体： 运动强度和时间因人而异。如果你发现某种运动让你感到过度疲劳或影响夜间入睡，及时调整。
- 安全第一： 如果你有任何健康问题，在开始新的运动计划前，务必咨询医生或专业的健身教练。
5. 日间恢复：6小时睡眠后，如何保持16小时清醒高效
你已经通过科学的方法，把夜间的6小时睡眠打造成了“高浓度充电”模式。那么，剩下的16小时清醒时间，你该怎么管理，才能确保精力充沛，而不是在下午就感到“电量耗尽”呢？这就需要我们运用一些日间恢复的技巧，就像给你的“能量条”不断补充“小电量”，避免出现大幅度的能量波动。
5.1 微休息技巧：10分钟“充电小睡”替代“咖啡依赖”
即使你的夜间睡眠质量再高，一天漫长的工作和生活仍然会对你的精力造成消耗。到了下午，很多人会感到精力下降、注意力不集中，这时候，最常见的选择就是来一杯咖啡续命。但如果你想真正做到精力充沛，而不是过度依赖咖啡因，那么“微休息”技巧——特别是高效的午间小睡，将是你的秘密武器。
午间小睡：20分钟的“黄金充电时间”
午间小睡的好处，可能比你想象的还要多。它能有效缓解疲劳，提升认知功能，改善情绪。但小睡也有讲究，时长是关键！
为什么是20分钟？ 大多数研究都指出，10分钟的小睡效果最佳，尽管20分钟的小睡也有益处 84。10-20分钟的午间小睡能让你进入浅层睡眠，恢复精力，但又不会进入深度睡眠。这样，醒来后你会感到神清气爽，迅速恢复状态，而不会出现所谓的“睡眠惰性”（Sleep Inertia）——也就是刚睡醒时感到头昏脑胀、反应迟钝的现象 85。
如何实践：
- 设定闹钟： 严格将小睡时间控制在10-20分钟内。
- 创造条件： 找一个相对安静、光线较暗的环境。如果条件不允许，戴上眼罩和耳塞也能有所帮助。
- 醒后快速清醒： 醒来后，可以拍拍脸、喝杯水、去洗手间用冷水洗洗脸，或者起身走动几分钟。如果条件允许，用清凉的喷雾喷一下脸，也能帮助你更快地摆脱残留的困倦感。
替代“咖啡依赖”： 午间小睡是一种更自然、更健康的恢复精力的方式。通过规律的小睡，你可以减少对咖啡因的依赖，避免咖啡因对夜间睡眠的潜在影响。
咖啡因：合理摄入，避免“饮鸩止渴”
咖啡因是一种强大的提神剂，适量使用可以帮助我们保持清醒和专注。但如果不了解它的作用机制和半衰期，就很容易变成“饮鸩止渴”，不仅影响夜间睡眠，还可能让你陷入恶性循环。
- 半衰期： 咖啡因的半衰期因个体差异而异，对咖啡因敏感的个体可能具有更高的半衰期和更大的清除率变异性 86。这意味着，即使到了晚上，你体内仍然有咖啡因在发挥作用，可能干扰你的入睡和睡眠质量。
- 避免下午3点后摄入： 为了不影响夜间睡眠，最安全的做法是下午3点之后就避免摄入任何含有咖啡因的饮品（包括咖啡、茶、能量饮料、可乐等）。一项研究发现，即使是睡前4小时摄入400毫克咖啡因（约两杯大杯咖啡的量），也会显著影响睡眠，包括入睡时间延长、睡眠碎片化等 87。而另有研究也指出，即使在睡前5小时摄入咖啡因，仍会扰乱后续的白日恢复性睡眠 88。
- 个人敏感性： 每个人对咖啡因的敏感性不同。例如，睡眠质量较差的人群对咖啡因的生理反应可能与正常睡眠者不同 86。如果你发现即使是上午喝咖啡也会影响夜间睡眠，那么你可能属于咖啡因敏感型，需要进一步减少摄入量或更早地停止摄入。青少年，特别是患有注意力缺陷多动症（ADHD）的青少年，对咖啡因的影响可能更敏感，下午和晚上摄入咖啡因会显著增加他们的睡眠问题 89。
- “咖啡因小睡”（Caffeine Nap）： 一种结合了咖啡因和小睡的技巧。在小睡前摄入少量咖啡因，然后立即小睡20分钟。由于咖啡因需要20-30分钟才能开始发挥作用，等你醒来时，咖啡因的提神效果正好开始显现，能让你更快地进入清醒状态，达到更好的提神效果。但这种方法依然要注意咖啡因的总摄入量和停止摄入时间。
通过掌握午间小睡的技巧，并合理管理咖啡因的摄入，你就能在6小时夜间睡眠的基础上，更好地维持白天的精力水平，避免下午的“能量谷”，从而更高效地度过剩下的16小时清醒时间。
5.2 精力管理：用“能量波峰”规划一天任务
既然我们已经学会了如何通过夜间高质量睡眠和日间微休息来补充能量，那么接下来，更重要的是如何聪明地“分配”这些能量，让它们发挥最大的效用。这就像你有一笔有限的资金，如果能合理规划，就能创造出更大的价值。我们的精力也是一样，它不是一成不变的，而是有高有低，呈现出波动的状态。这就是我们常说的“能量波峰”和“能量波谷”。
了解并利用这些能量波峰，能让你在6小时睡眠后，依然能保持16小时的清醒高效。其核心思想就是：在精力充沛的时候做最需要脑力的工作，在精力低谷期安排轻松的任务，并避免长时间连续工作。
这同样要归功于我们身体的昼夜节律（生物钟）。它不仅仅控制着我们的睡眠，也调控着我们白天的代谢、认知功能和情绪等，使它们在一天中呈现规律性的变化 90。
上午9-11点：大脑的“黄金工作时段”
- 特点： 这段时间，你的身体刚从夜间修复中恢复，皮质醇（一种与警觉性和专注力相关的激素）水平达到高峰。你的大脑处于最清醒、最活跃的状态，逻辑思维能力、专注力和解决问题的能力都达到一天中的巅峰。
- 任务规划： 抓住这个“黄金时段”，处理那些最需要高度专注、创新思维和解决复杂问题的任务。例如：撰写报告、策划方案、学习新知识、进行头脑风暴、做重要的决策等。把这些“硬骨头”放在上午解决，你会发现效率会高得多，而且不容易感到疲惫。
下午14-16点：体温回升期，适宜协作与沟通
- 特点： 午饭后，很多人会感到轻微的困倦（也就是我们前面提到的“饭困”），这是正常的生理现象，你的核心体温会略微下降。但随着午后，体温会逐渐回升。这段时间，虽然认知功能的巅峰期已过，但精力会开始回升，而且相对放松，更适合进行一些互动性、协作性的任务。
- 任务规划： 安排会议、沟通协调、回复邮件、处理常规性事务、进行数据整理或一些不太需要创造性的重复性工作。如果你需要与同事讨论问题，这段时间也是不错的选择，因为大家的整体状态相对稳定。
傍晚17-19点：运动期，释放压力，为高效休息做准备
- 特点： 傍晚时分，进行适当的体育锻炼不仅能释放工作压力，还能帮助你更好地从一天的工作状态中切换出来，为夜间的优质睡眠做准备。
- 任务规划： 安排健身、跑步、瑜伽或任何你喜欢的运动。运动可以促进内啡肽的释放，带来愉悦感，同时也能帮助消耗多余的能量，让身体产生自然的疲惫感，从而促进夜间更好的睡眠。
避免长时间连续工作：大脑的“疲劳周期”
- 大脑工作原理： 我们的注意力是有限的资源。长时间高度专注地工作会导致效率下降和疲劳。
- 如何实践：
- 番茄工作法： 你可以尝试“番茄工作法”，即专注工作25分钟，然后休息5分钟；每完成4个番茄钟（大约100分钟），就进行一个较长时间的休息（15-30分钟）。这种方式能有效避免大脑长时间疲劳，保持较高的工作效率。
- 间歇性休息： 即使没有严格按照番茄工作法，也要确保每工作一段时间就起身活动一下，喝水，做一些简单的拉伸，或者仅仅是眺望远方几分钟。这能让你的大脑得到短暂的放松和恢复，避免过度疲劳，从而让你在剩余的清醒时间里，也能保持较高的专注力和精力。
通过这种“精力管理”的方法，你不是在硬撑着度过16小时，而是在有意识地利用身体的自然规律，让精力在一天中保持相对平稳的高效状态。这样，即使只有6小时的夜间睡眠，你也能自信地面对全天的挑战。
6. 长期维护：6小时睡眠的可持续性关键
前面我们已经从睡眠的生理机制、环境优化、饮食运动以及日间精力管理等多个维度，详细探讨了如何通过科学调整，让6小时睡眠也能实现“高浓度充电”，并保持一整天的精力充沛。然而，这并非一劳永逸。身体是动态变化的，生活节奏也可能打乱原有的平衡。因此，想要长期维持这种高效的睡眠模式，就需要一套持续的“维护机制”，就像定期给汽车做保养一样，确保各个部件都能良好运转。
6.1 定期“睡眠体检”：用数据调整你的睡眠方案
你每天只睡6小时，如何确定这种模式真的适合你，而不是在悄悄透支身体？这就需要定期对自己的睡眠进行“体检”，用数据说话，客观评估睡眠质量，并根据身体的真实反应动态调整你的睡眠方案。这就像在进行一场个人化的科学实验，而你就是这个实验的主角。
智能设备：你的“睡眠私人教练”
现在市面上有各种智能手环、智能戒指（如Oura ring 91）、睡眠APP等可穿戴设备，它们就像你的“睡眠私人教练”，能够无创地监测你的睡眠，并提供详细的数据报告。虽然这些消费级设备在某些参数上与专业的“多导睡眠图”（polysomnography, PSG）仍有差距 92，例如在区分清醒与睡眠方面表现较好（睡眠检测敏感度可达96%），但在识别具体的睡眠阶段（如浅睡、深睡、REM睡眠）时准确性会降低 91，并且可能低估严重的睡眠障碍 93，但它们仍然是普通人了解自身睡眠模式的便捷工具 94。一些更先进的移动应用甚至可以记录打鼾声音 9596。
你可以通过这些设备监测以下关键指标：
- 睡眠效率（Sleep Efficiency, SE）： 这是衡量你睡眠质量的重要指标，计算公式是（实际睡眠时长 / 卧床时间）× 100%。如果你的卧床时间是6小时，实际睡着的时间是5.5小时，那么你的睡眠效率就是（5.5/6）×100% ≈ 91.6%。通常，睡眠效率达到85%以上被认为是良好的睡眠质量。如果你的睡眠效率低于这个标准，说明你在床上花费了大量时间却没有真正睡着，需要检查睡眠环境或入睡习惯。
- 深睡占比（Slow-Wave Sleep, SWS）： 深睡（N3阶段）是身体修复、精力恢复最关键的时期。理想情况下，深睡应该占总睡眠时间的15%以上。一些设备能大致估算出深睡的时间和比例。如果发现深睡占比过低，可能需要调整睡前习惯，例如避免睡前剧烈运动、保持卧室黑暗安静等，以促进深度睡眠。值得注意的是，深睡的减少可能与痴呆症风险增加有关 97。
- REM睡眠占比： REM睡眠对情绪调节和记忆巩固至关重要。理想情况下，REM睡眠应占总睡眠时间的20-25%。如果REM睡眠占比异常，也需要关注。
- 夜间觉醒次数和时长： 频繁的夜间觉醒会打断睡眠周期，严重影响睡眠质量。设备通常能记录你夜间醒来的次数和每次醒来的时长。如果夜间觉醒次数超过3次，或者醒来总时长过长，就需要寻找原因，比如是否起夜频繁、是否被噪音吵醒、是否有呼吸暂停等问题。
- 入睡时间： 从躺下到真正入睡的时间。如果经常躺下超过30分钟还无法入睡，则可能存在入睡困难，需要调整入睡前活动。
睡眠日记：自我观察的“最佳伴侣”
虽然智能设备能提供客观数据，但结合睡眠日记进行主观感受的记录同样重要 98。每天早上醒来，花几分钟记录以下内容：
- 昨晚几点入睡？几点醒来？ （与设备数据进行比对，看看是否存在偏差）
- 睡前做了什么？ （有助于发现影响入睡的习惯）
- 夜间是否醒来？醒来几次？ （与设备数据相互验证）
- 醒来时的感受： 是否感到清醒、精力充沛？还是昏昏沉沉、疲惫不堪？
- 白天的精力水平： 上午、下午是否有犯困、注意力不集中的情况？
- 情绪状态： 是否感到烦躁、焦虑？
通过这些主观感受，你可以更好地理解数据背后的意义，找到数据异常与自身感受之间的关联。例如，设备显示深睡比例下降，而你恰好感觉白天精力不济，那么就可以有针对性地进行调整。
动态调整：你的“睡眠优化师”
有了数据和自我观察，你就可以成为自己的“睡眠优化师”，根据反馈进行动态调整。
- 定期回顾： 每周或每两周回顾一次睡眠数据和日记。看看在过去的这段时间里，你的睡眠效率、深睡占比是否稳定，白天的精力状态是否理想。
- 小步快跑，逐一调整： 如果发现问题，不要一下子改变所有习惯。比如，如果你怀疑睡前玩手机影响了深睡，就先尝试一周睡前一小时不碰手机，然后观察数据和感受的变化。
- 关注压力与激素： 睡眠与压力、皮质醇等激素水平密切相关 99。持续的压力可能会影响睡眠质量，导致即使睡足6小时也感觉不到恢复。这时，除了调整睡眠本身，还需要关注压力管理。
- 寻求专业帮助： 如果你尝试了多种方法，睡眠质量依然不佳，或者智能设备监测出有持续的严重异常（如频繁呼吸暂停），务必及时咨询睡眠医生或专业人士。他们可以为你进行更专业的评估，并提供个性化的干预方案。
通过这种持续的“睡眠体检”和动态调整，你就能确保自己每天的6小时睡眠是真正高效且可持续的。它会让你更了解自己的身体，掌握调整的主动权，最终实现长期精力充沛的目标。
6.2 警惕“隐形消耗”：压力与情绪如何偷走你的睡眠质量
即使你严格遵循了上述所有睡眠优化和精力管理的方法，却依然感到难以入睡、夜间多梦、醒来疲惫，那么你可能正在经历一种“隐形消耗”——压力与情绪对睡眠的侵蚀。这就像是一个无形的盗贼，悄悄偷走你辛苦积累的睡眠成果，让你“睡够了但没恢复”。
我们的身心是紧密相连的。当一个人长期处于压力、焦虑或负面情绪中时，身体会启动一系列的应激反应，其中最核心的就是下丘脑-垂体-肾上腺（HPA）轴的激活 100。HPA轴是身体的“压力应对系统”，它会分泌一种叫做皮质醇的激素，也就是我们常说的“压力激素”。
皮质醇在正常情况下是身体的“好帮手”，它在清晨达到高峰，帮助我们保持清醒、专注和活力 100。但当慢性压力（比如工作焦虑、家庭矛盾、学业压力等）持续存在时，皮质醇水平就会长期居高不下，甚至在夜晚也无法有效降低 100101。这就像身体的“警报系统”一直处于开启状态，随时准备应对威胁。
皮质醇过高如何偷走你的睡眠？
- 影响入睡： 夜晚过高的皮质醇可能会使人难以入睡，即使躺在床上也很难放松下来。
- 干扰睡眠质量： 长期慢性压力和皮质醇水平的失调会干扰正常的睡眠模式，可能导致睡眠碎片化，夜间觉醒次数增加，影响深度睡眠和快速眼动（REM）睡眠的比例，从而降低睡眠的恢复效果。睡眠被认为在情绪大脑处理中扮演着重要角色，而睡眠异常与情绪障碍的发生和维持之间存在关联 102。
- 加剧焦虑和抑郁： 长期睡眠不足和皮质醇失调会形成一个恶性循环，加重焦虑、抑郁等情绪问题，而这些情绪反过来又会进一步恶化睡眠质量 103104105。研究显示，医学专业的学生长时间使用智能手机与睡眠质量差、抑郁、焦虑和压力水平升高显著相关 106。
如何应对这些“隐形消耗”？
识别并正视压力源： 很多人可能没有意识到自己正处于慢性压力中，或者习惯性地忽略负面情绪。第一步是学会识别自己的压力源，并正视这些情绪，而不是压抑它们。
学会放松技巧：“4-7-8呼吸法”
这是一种简单易学、随时随地都能进行的呼吸练习，有助于快速放松身心，降低皮质醇水平，为入睡做好准备。它源于瑜伽的呼吸法，被称为“身心平静剂”。
方法：
- 呼气（4秒）： 舌尖抵住上颚，在吐气时发出“嘶”的声音，将肺部空气全部呼出。
- 吸气（7秒）： 闭上嘴巴，用鼻子轻轻吸气，默数1-2-3-4。
- 屏息（8秒）： 屏住呼吸，默数1-2-3-4-5-6-7。
- 呼气（8秒）： 再次发出“嘶”的声音，通过嘴巴将气完全呼出，默数1-2-3-4-5-6-7-8。
- 重复： 完成一次呼吸循环。每天重复3-4次，睡前重复数次，直到感到放松。
原理： 呼吸练习，如源自瑜伽的调息法（Pranayama），有助于促进身心放松，从而减少焦虑，有助于改善睡眠。一项针对慢性阻塞性肺病患者的研究成功证明，调息法与运动耐力的改善相关 107。一项针对大学生的研究也显示，为期14周的结构化呼吸练习项目能显著改善主观幸福感、情绪调节和睡眠质量，并减少忧虑水平 108。
培养正念与冥想： 正念练习可以帮助你更好地觉察当下，减少对过去和未来的过度担忧，从而减轻压力和焦虑 100。研究表明，基于正念的瑜伽练习能显著改善护士和医护人员的压力、倦怠感和睡眠质量 109。
寻求专业帮助：心理咨询
如果长期的压力和负面情绪已经严重影响了你的生活和睡眠，甚至出现了失眠、焦虑症或抑郁症的症状，那么寻求专业的心理咨询或心理治疗是非常有必要的。心理咨询师可以帮助你识别情绪模式，学习有效的应对策略，从根本上减少情绪内耗，避免身体长期处于应激状态。
管理好压力和情绪，就像给你的身体加了一层“保护罩”，避免内部能量的无谓消耗。只有身心都得到放松和平衡，你的6小时睡眠才能真正实现高效修复，让你在清醒的16小时里，保持持久的精力与活力。
内容由 AI 生成，仅供参考，请仔细甄别
参考文献
1The molecular genetics of human sleep.PubMed
Luoying Zhang, Ying-Hui Fu
Eur J Neurosci. 2020 Jan;51(1):422-428. doi: 10.1111/ejn.14132. Epub 2018 Sep 20.
It has been known for many years that genetic influences account for some of the individual differences in human sleep parameters, but the underlying molecular mechanisms remain unclear. With major advances of molecular biology and the recognition of heritable sleep behaviors in humans over the past 30 years, a number of genetic variants have been identified to be associated with human sleep timing, duration and quality, both in healthy individuals and under pathological conditions. Some of these variants were further validated and characterized in animal models, shedding light on the mechanism of how these variants likely alter sleep in humans, which may provide new insights into developing more effective treatments to improve human sleep.
2Mammalian Reverse Genetics without Crossing Reveals Nr3a as a Short-Sleeper Gene.PubMed
Genshiro A Sunagawa, Kenta Sumiyama, Maki Ukai-Tadenuma, et al.
Cell Rep. 2016 Jan 26;14(3):662-677. doi: 10.1016/j.celrep.2015.12.052. Epub 2016 Jan 7.
The identification of molecular networks at the system level in mammals is accelerated by next-generation mammalian genetics without crossing, which requires both the efficient production of whole-body biallelic knockout (KO) mice in a single generation and high-performance phenotype analyses. Here, we show that the triple targeting of a single gene using the CRISPR/Cas9 system achieves almost perfect KO efficiency (96%-100%). In addition, we developed a respiration-based fully automated non-invasive sleep phenotyping system, the Snappy Sleep Stager (SSS), for high-performance (95.3% accuracy) sleep/wake staging. Using the triple-target CRISPR and SSS in tandem, we reliably obtained sleep/wake phenotypes, even in double-KO mice. By using this system to comprehensively analyze all of the N-methyl-D-aspartate (NMDA) receptor family members, we found Nr3a as a short-sleeper gene, which is verified by an independent set of triple-target CRISPR. These results demonstrate the application of mammalian reverse genetics without crossing to organism-level systems biology in sleep research.
3Selection for long and short sleep duration in Drosophila melanogaster reveals the complex genetic network underlying natural variation in sleep.PubMed
Susan T Harbison, Yazmin L Serrano Negron, Nancy F Hansen, et al.
PLoS Genet. 2017 Dec 14;13(12):e1007098. doi: 10.1371/journal.pgen.1007098. eCollection 2017 Dec.
Why do some individuals need more sleep than others? Forward mutagenesis screens in flies using engineered mutations have established a clear genetic component to sleep duration, revealing mutants that convey very long or short sleep. Whether such extreme long or short sleep could exist in natural populations was unknown. We applied artificial selection for high and low night sleep duration to an outbred population of Drosophila melanogaster for 13 generations. At the end of the selection procedure, night sleep duration diverged by 9.97 hours in the long and short sleeper populations, and 24-hour sleep was reduced to 3.3 hours in the short sleepers. Neither long nor short sleeper lifespan differed appreciably from controls, suggesting little physiological consequences to being an extreme long or short sleeper. Whole genome sequence data from seven generations of selection revealed several hundred thousand changes in allele frequencies at polymorphic loci across the genome. Combining the data from long and short sleeper populations across generations in a logistic regression implicated 126 polymorphisms in 80 candidate genes, and we confirmed three of these genes and a larger genomic region with mutant and chromosomal deficiency tests, respectively. Many of these genes could be connected in a single network based on previously known physical and genetic interactions. Candidate genes have known roles in several classic, highly conserved developmental and signaling pathways-EGFR, Wnt, Hippo, and MAPK. The involvement of highly pleiotropic pathway genes suggests that sleep duration in natural populations can be influenced by a wide variety of biological processes, which may be why the purpose of sleep has been so elusive.
4Sleep loss, learning capacity and academic performance.PubMed
Giuseppe Curcio, Michele Ferrara, Luigi De Gennaro
Sleep Med Rev. 2006 Oct;10(5):323-37. doi: 10.1016/j.smrv.2005.11.001. Epub 2006 Mar 24.
At a time when several studies have highlighted the relationship between sleep, learning and memory processes, an in-depth analysis of the effects of sleep deprivation on student learning ability and academic performance would appear to be essential. Most studies have been naturalistic correlative investigations, where sleep schedules were correlated with school and academic achievement. Nonetheless, some authors were able to actively manipulate sleep in order to observe neurocognitive and behavioral consequences, such as learning, memory capacity and school performance. The findings strongly suggest that: (a) students of different education levels (from school to university) are chronically sleep deprived or suffer from poor sleep quality and consequent daytime sleepiness; (b) sleep quality and quantity are closely related to student learning capacity and academic performance; (c) sleep loss is frequently associated with poor declarative and procedural learning in students; (d) studies in which sleep was actively restricted or optimized showed, respectively, a worsening and an improvement in neurocognitive and academic performance. These results may been related to the specific involvement of the prefrontal cortex (PFC) in vulnerability to sleep loss. Most methodological limitations are discussed and some future research goals are suggested.
5Combinations of Physical Activity, Sedentary Behavior, and Sleep Duration and Their Associations With Physical, Psychological, and Educational Outcomes in Children and Adolescents: A Systematic Review.PubMed
Katrina Wilhite, Bridget Booker, Bo-Huei Huang, et al.
Am J Epidemiol. 2023 Apr 6;192(4):665-679. doi: 10.1093/aje/kwac212.
We conducted a systematic review to evaluate combinations of physical activity, sedentary behavior, and sleep duration (defined as "movement behaviors") and their associations with physical, psychological, and educational outcomes in children and adolescents. MEDLINE, CINAHL, PsychInfo, SPORTDiscus, PubMed, EMBASE, and ERIC were searched in June 2020. Included studies needed to 1) quantitatively analyze the association of 2 or more movement behaviors with an outcome, 2) analyze a population between 5 and 17 years of age, and 3) include at least an English abstract. We included 141 studies. Most studies included the combination of physical activity and sedentary behavior in their analyses. Sleep was studied less frequently. In combination, a high level of physical activity and a low level of sedentary behavior were associated with the best physical health, psychological health, and education-related outcomes. Sleep was often included in the combination that was associated with the most favorable outcomes. Sedentary behavior had a stronger influence in adolescents than in children and tended to be associated more negatively with outcomes when it was defined as screen time than when defined as overall time spent being sedentary. More initiatives and guidelines combining all 3 movement behaviors will provide benefit with regard to adiposity, cardiometabolic risk factors, cardiorespiratory fitness, muscular physical fitness, well-being, health-related quality of life, mental health, academic performance, and cognitive/executive function.
6Sleep Duration and Executive Function in Adults.PubMed
Aayushi Sen, Xin You Tai
Curr Neurol Neurosci Rep. 2023 Nov;23(11):801-813. doi: 10.1007/s11910-023-01309-8. Epub 2023 Nov 14.
PURPOSE OF REVIEW: To review the literature examining the relationship between sleep and cognition, specifically examining the sub-domain of executive function. We explore the impact of sleep deprivation and the important question of how much sleep is required for optimal cognitive performance. We consider how other sleep metrics, such as sleep quality, may be a more meaningful measure of sleep. We then discuss the putative mechanisms between sleep and cognition followed by their contribution to developing dementia. RECENT FINDINGS: Sleep duration and executive function display a quadratic relationship. This suggests an optimal amount of sleep is required for daily cognitive processes. Poor sleep efficiency and sleep fragmentation are linked with poorer executive function and increased risk of dementia during follow-up. Sleep quality may therefore be more important than absolute duration. Biological mechanisms which may underpin the relationship between sleep and cognition include brain structural and functional changes as well as disruption of the glymphatic system. Sleep is an important modifiable lifestyle factor to improve daily cognition and, possibly, reduce the risk of developing dementia. The impact of optimal sleep duration and sleep quality may have important implications for every ageing individual.
7Brain neural patterns and the memory function of sleep.PubMed
Gabrielle Girardeau, Vítor Lopes-Dos-Santos
Science. 2021 Oct 29;374(6567):560-564. doi: 10.1126/science.abi8370. Epub 2021 Oct 28.
Sleep is crucial for healthy cognition, including memory. The two main phases of sleep, REM (rapid eye movement) and non-REM sleep, are associated with characteristic electrophysiological patterns that are recorded using surface and intracranial electrodes. These patterns include sharp-wave ripples, cortical slow oscillations, delta waves, and spindles during non-REM sleep and theta oscillations during REM sleep. They reflect the precisely timed activity of underlying neural circuits. Here, we review how these electrical signatures have been guiding our understanding of the circuits and processes sustaining memory consolidation during sleep, focusing on hippocampal theta oscillations and sharp-wave ripples and how they coordinate with cortical patterns. Finally, we highlight how these brain patterns could also sustain sleep-dependent homeostatic processes and evoke several potential future directions for research on the memory function of sleep.
8Understanding the Neural Mechanisms of General Anesthesia from Interaction with Sleep-Wake State: A Decade of Discovery.PubMed
Wei-Wei Bao, Shan Jiang, Wei-Min Qu, et al.
Pharmacol Rev. 2023 May;75(3):532-553. doi: 10.1124/pharmrev.122.000717. Epub 2023 Jan 10.
The development of cutting-edge techniques to study specific brain regions and neural circuits that regulate sleep-wake brain states and general anesthesia (GA), has increased our understanding of these states that exhibit similar neurophysiologic traits. This review summarizes current knowledge focusing on cell subtypes and neural circuits that control wakefulness, rapid eye movement (REM) sleep, non-REM sleep, and GA. We also review novel insights into their interactions and raise unresolved questions and challenges in this field. Comparisons of the overlapping neural substrates of sleep-wake and GA regulation will help us to understand sleep-wake transitions and how anesthetics cause reversible loss of consciousness. SIGNIFICANCE STATEMENT: General anesthesia (GA), sharing numerous neurophysiologic traits with the process of natural sleep, is administered to millions of surgical patients annually. In the past decade, studies exploring the neural mechanisms underlying sleep-wake and GA have advanced our understanding of their interactions and how anesthetics cause reversible loss of consciousness. Pharmacotherapies targeting the neural substrates associated with sleep-wake and GA regulations have significance for clinical practice in GA and sleep medicine.
9REM sleep, REM parasomnias, REM sleep behaviour disorder.PubMed
Anna Szûcs, Carlotta Mutti, Anikó Papp, et al.
Ideggyogy Sz. 2022 May 30;75(5-06):171-182. doi: 10.18071/isz.75.0171.
We review the literature on REM parasomnias, and their the underlying mechanisms. Several REM parasomnias are consistent with sleep dissociations, where certain elements of the REM sleep pattern emerge in an inadequate time (sleep paralysis, hypnagogic hallucinations and cataplexy) or are absent/partial in their normal REM sleep time (REM sleep without atonia, underlying REM sleep behavior disorder). The rest of REM parasomnias (sleep related painful erection, catathrenia) may have other still unclear mechanisms. REM parasomnias deserve attention, because in addition to disturbing sleep and causing injuries, they may shed light on REM sleep functions as well as the heterogeneous etiologies of parasomnias. One of them, REM sleep behavior disorder has special importance as a warning sign of evolving neurodegenerative conditions mainly synucleinopathies (some cases synucleinopathies themselves) and it is a model parasomnia revealing that parasomnias may have by autoimmune, iatrogenic and even psychosomatic etiologies.
10English translation of the first study reporting cyclical periods of increased respiration and eye and body motility during sleep in infants in 1926, with commentary.PubMed
Kristina Denisova
Sleep. 2024 Jan 11;47(1). doi: 10.1093/sleep/zsad219.
This is the first English translation of the work Periodic phenomena in the sleep in children, published in 1926 in the Journal Novoe v refleksologii i fiziologii nervnoi sistemy (Vol. 2, pp. 338-345) by Maria Denisova and Nicholai Figurin; it is the first study to report data on what is currently termed rapid eye movement (REM) sleep. The authors acquired continuous quantitative respiration data, as well as, eye and body movements during sleep in children for up to 6 hours, and discovered several novel features of sleep cycles in healthy infants from birth to about 1 year of age. First, the study reports cyclical periods of increased respiration and eye and body movements, with rapid ocular movements visible under relaxed eyelids (separation: 0.5-1 mm). These observations suggest atonia of REM sleep. Second, the length of the complete cycle (alternating active and quiet sleep phases or states) is about 50 minutes, an estimate that is consistent with later work. Third, the study identifies infant-specific ordering of sleep states, with the active phase beginning after sleep onset, followed by the quiescence phase. Importantly, these published data on sleep cycles precede all published studies related to the state now termed REM sleep by about 30 years (i.e. publishing in Science and in the Journal of Applied Physiology in the 1950s by Eugene Aserinski and Nathaniel Kleitman). In the historical commentary accompanying this translation, the findings of those later works are carefully compared to the original data on respiration and ocular and body motility cycles during sleep in infants, first reported and published by Denisova and Figurin (1926).
11Infralimbic activity during REM sleep facilitates fear extinction memory.PubMed
Jiso Hong, Kyuhyun Choi, Marc V Fuccillo, et al.
Curr Biol. 2024 May 20;34(10):2247-2255.e5. doi: 10.1016/j.cub.2024.04.018. Epub 2024 May 6.
Rapid eye movement (REM) sleep is known to facilitate fear extinction and play a protective role against fearful memories. Consequently, disruption of REM sleep after a traumatic event may increase the risk for developing PTSD. However, the underlying mechanisms by which REM sleep promotes extinction of aversive memories remain largely unknown. The infralimbic cortex (IL) is a key brain structure for the consolidation of extinction memory. Using calcium imaging, we found in mice that most IL pyramidal neurons are intensively activated during REM sleep. Optogenetically suppressing the IL specifically during REM sleep within a 4-h window after auditory-cued fear conditioning impaired extinction memory consolidation. In contrast, REM-specific IL inhibition after extinction learning did not affect the extinction memory. Whole-cell patch-clamp recordings demonstrated that inactivating IL neurons during REM sleep depresses their excitability. Together, our findings suggest that REM sleep after fear conditioning facilitates fear extinction by enhancing IL excitability and highlight the importance of REM sleep in the aftermath of traumatic events for protecting against traumatic memories.
12Sleep-dependent memory processing.PubMed
Matthew P Walker
Harv Rev Psychiatry. 2008;16(5):287-98. doi: 10.1080/10673220802432517.
While the functions of sleep remain largely unknown, one exciting hypothesis is that sleep contributes importantly to processes of memory and brain plasticity. Over the last decade, a large body of work has provided substantive evidence supporting this role of sleep in what is becoming known as sleep-dependent memory processing. This review offers a summary of these data, focusing specifically on the role of sleep in (1) memory encoding, (2) memory consolidation (along with the brain basis of this process), and (3) neural plasticity. The clinical ramifications of such findings are also explored.
14Nighttime Sleep and Respiratory Disturbances in Individuals Receiving Methadone to Treat Opioid Use Disorder.PubMed
Myles Finlay, Julie A Erwin, Lillian Skeiky, et al.
J Addict Nurs. 2023;34(4):E180-E188. doi: 10.1097/JAN.0000000000000470. Epub 2023 Sep 28.
Opioids are a leading cause of drug overdose deaths in the United States. Methadone used as medication for opioid use disorder (MOUD) reduces drug cravings and promotes abstinence. However, individuals in methadone-based MOUD treatment commonly report subjective sleep complaints and are at risk for respiratory depression from opioids. We investigated nighttime sleep and respiratory function in eight individuals (six women, two men; ages 31-68 years) in their first 90 days of methadone-based MOUD treatment. Participants underwent overnight cardiorespiratory polysomnography. Sleep and respiratory variables were characterized with descriptive statistics for comparison to reference data from similarly aged healthy adults. Although participants spent 8.1 ± 0.3 hours (mean ± SD ) in bed, their total sleep time was only 6.8 ± 1.3 hours. They exhibited longer sleep latency and intermittent wakefulness. Sleep structure was irregular, with disrupted sleep cycles. Participants also displayed a decreased amount of N1 sleep and an increased amount of N3 sleep, compared with reference data. Participants showed respiratory depression, with an average apnea-hypopnea index of 16.5 ± 8.9 events per hour. Central sleep apneas comprised 69.1% ± 20.9% of the respiratory events. A Cheyne-Stokes-like breathing pattern, consisting of 30-second cycles of three central sleep apneas, was observed in 75% of participants. Our results suggest that individuals early in methadone-based MOUD treatment experience disordered sleep and respiratory disturbances. Such nighttime physiological changes may have serious long-term health consequences and contribute to unintended overdose rates. Identifying and treating MOUD individuals with sleep apnea could reduce risk of death.
15Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: A randomized controlled trial.PubMed
Heather A Hausenblas, Tarah Lynch, Stephanie Hooper, et al.
Sleep Med X. 2024 Aug 17;8:100121. doi: 10.1016/j.sleepx.2024.100121. eCollection 2024 Dec 15.
OBJECTIVE/BACKGROUND: Sleep problems challenge overall wellbeing. Magnesium has been implicated to benefit sleep, although the clinical evidences varied based on the magnesium source used. Magnesium L-threonate (MgT) is a promising intervention due to its brain bioavailability and effects on cognition, memory and mood. We investigated MgT supplementation on sleep quality and daily function. PATIENTS/METHODS: Eighty 35-55-year-olds with self-assessed sleep problems participated in a randomized, double-blind, placebo-controlled, parallel-arm study, taking 1 g/day of MgT or placebo for 21 days. Sleep and daily behaviors were measured subjectively using standardized questionnaires including the Insomnia Severity Index, Leeds Sleep Evaluation Questionnaire, and Restorative Sleep Questionnaire, and objectively using an Oura ring. The Profile of Mood States questionnaire and a daily diary were used to evaluate mood, energy and productivity, and record any safety concerns. RESULTS: The MgT group maintained good sleep quality and daytime functioning, while placebo declined. From objective Oura ring measurements, MgT significantly (p < 0.05) improved placebo deep sleep score, REM sleep score, light sleep time, and activity and readiness parameters activity score, activity daily movement score, readiness score, readiness activity balance, and readiness sleep balance. From subjective questionnaires, MgT significantly (p < 0.05) improved placebo behavior upon awakening, energy and daytime productivity, grouchiness, mood and mental alertness. MgT was safe and well tolerated. CONCLUSIONS: This showed MgT improved sleep quality, especially deep/REM sleep stages, improved mood, energy, alertness, and daily activity and productivity. These are consistent with how MgT works in neuron cells and animal models, suggesting broader positive impacts on overall brain health.
16Sleep Deprivation.PubMed
Robert M Abrams
Obstet Gynecol Clin North Am. 2015 Sep;42(3):493-506. doi: 10.1016/j.ogc.2015.05.013.
Sleep deprivation occurs when inadequate sleep leads to decreased performance, inadequate alertness, and deterioration in health. It is incompletely understood why humans need sleep, although some theories include energy conservation, restoration, and information processing. Sleep deprivation has many deleterious health effects. Residency programs have enacted strict work restrictions because of medically related errors due to sleep deprivation. Because obstetrics is an unpredictable specialty with long irregular hours, enacting a hospitalist program enhances patient safety, decreases malpractice risk, and improves the physician's quality of life by allowing obstetricians to get sufficient rest.
17The metabolic burden of sleep loss.PubMed
Sebastian M Schmid, Manfred Hallschmid, Bernd Schultes
Lancet Diabetes Endocrinol. 2015 Jan;3(1):52-62. doi: 10.1016/S2213-8587(14)70012-9. Epub 2014 Mar 25.
In parallel with the increasing prevalence of obesity and type 2 diabetes, sleep loss has become common in modern societies. An increasing number of epidemiological studies show an association between short sleep duration, sleep disturbances, and circadian desynchronisation of sleep with adverse metabolic traits, in particular obesity and type 2 diabetes. Furthermore, experimental studies point to distinct mechanisms by which insufficient sleep adversely affects metabolic health. Changes in the activity of neuroendocrine systems seem to be major mediators of the detrimental metabolic effects of insufficient sleep, through favouring neurobehavioural outcomes such as increased appetite, enhanced sensitivity to food stimuli, and, ultimately, a surplus in energy intake. The effect of curtailed sleep on physical activity and energy expenditure is less clear, but changes are unlikely to outweigh increases in food intake. Although long-term interventional studies proving a cause and effect association are still scarce, sleep loss seems to be an appealing target for the prevention, and probably treatment, of metabolic disease.
18The links between sleep duration, obesity and type 2 diabetes mellitus.PubMed
Christina Antza, Georgios Kostopoulos, Samiul Mostafa, et al.
J Endocrinol. 2021 Dec 13;252(2):125-141. doi: 10.1530/JOE-21-0155.
Global rates of obesity and type 2 diabetes mellitus (T2DM) are increasing globally concomitant with a rising prevalence of sleep deprivation and sleep disorders. Understanding the links between sleep, obesity and T2DM might offer an opportunity to develop better prevention and treatment strategies for these epidemics. Experimental studies have shown that sleep restriction is associated with changes in energy homeostasis, insulin resistance and β-cell function. Epidemiological cohort studies established short sleep duration as a risk factor for developing obesity and T2DM. In addition, small studies suggested that short sleep duration was associated with less weight loss following lifestyle interventions or bariatric surgery. In this article, we review the epidemiological evidence linking sleep duration to obesity and T2DM and plausible mechanisms. In addition, we review the impact of changes in sleep duration on obesity and T2DM.
19Sleep Disturbances Associated with Different Systems of the Body: Underlying Mechanisms Involved and Consequences.PubMed
Haitham Yahya Al-Farsi, Eman Younis Al-Fahdi, Mallak Abdullah Al-Balushi, et al.
Curr Med Chem. 2025;32(34):7624-7650. doi: 10.2174/0109298673350476250331181123.
Sleep is necessary for long-term health and well-being. Sleep is divided into the rapid eye movement (REM), and non-rapid eye movement (NREM) stages. The normal sleep pattern follows a 90-minute cycle, and within those cycles, the body undergoes a regenerative state, restoring various components used daily. A sleep disorder can be due to multiple factors, i.e., genetic, environmental, and individual factors. Short and long-term effects of sleep deprivation can have harmful effects. The immune system requires sufficient sleep to maintain optimal function, and sleep deprivation leads to the release of proinflammatory cytokines, which dysregulate the function of the immune system. Sleep deprivation affects the central nervous system, resulting in cognitive impairments and diseases related to decreased prefrontal cortex activity. Sleep disturbance affects the hypothalamus, secreting corticotrophin-releasing hormone, which results in the release of adrenocorticotropic hormone. This leads to the secretion of cortisol and catecholamines. Sleep disturbance causes reduced muscle glycogen concentration and gives rise to various gastrointestinal problems. Sleep disturbance affects the cardiovascular system which results in hypertension, cardiac ischemia, congestive cardiac failure, and arrhythmia. Sleep disturbances affect the endocrine system leading to insulin resistance, obesity, and metabolic syndrome. Interestingly, treatment of obstructive sleep apnea with continuous positive airway pressure was found to enhance metabolic status. We discuss the pharmacological, non-pharmacological, and surgical treatment options for sleep disorders. Understanding the mechanism of sleep disturbance and its association with different systems of the body may help in better treatment outcomes.
20The interrelationship between sleep, diet, and glucose metabolism.PubMed
Marie-Pierre St-Onge, Anna Cherta-Murillo, Christian Darimont, et al.
Sleep Med Rev. 2023 Jun;69:101788. doi: 10.1016/j.smrv.2023.101788. Epub 2023 Apr 28.
Obesity and type 2 diabetes (T2D) are increasingly common worldwide. While these disorders have increased in prevalence over the past several decades, there has been a concomitant reduction in sleep duration. Short sleep duration has been associated with higher rates of obesity and T2D, and the causality of these associations and their directionality, continue to necessitate evaluation. In this review we consider the evidence that sleep is an intrinsic factor in the development of obesity and chronic metabolic disorders, such as insulin resistance and T2D, while evaluating a potential bi-directional association. We consider the evidence that diet and meal composition, which are known to impact glycemic control, may have both chronic and acute impact upon sleep. Moreover, we consider that postprandial nocturnal metabolism and peripheral glycemia may affect sleep quality. We propose putative mechanisms whereby acute effects of nighttime glucose excursions may lead to increased sleep fragmentation. We conclude that dietary manipulations, particularly with respect to carbohydrate quality, may confer sleep benefits. Future research may seek to evaluate the effectiveness of synergistic nutrient strategies to promote sleep quality, with particular attention to carbohydrate quality, quantity, and availability as well as carbohydrate to protein ratio.
21Short sleep duration and dietary intake: epidemiologic evidence, mechanisms, and health implications.PubMed
Hassan S Dashti, Frank Ajl Scheer, Paul F Jacques, et al.
Adv Nutr. 2015 Nov 13;6(6):648-59. doi: 10.3945/an.115.008623. Print 2015 Nov.
Links between short sleep duration and obesity, type 2 diabetes, hypertension, and cardiovascular disease may be mediated through changes in dietary intake. This review provides an overview of recent epidemiologic studies on the relations between habitual short sleep duration and dietary intake in adults from 16 cross-sectional studies. The studies have observed consistent associations between short sleep duration and higher total energy intake and higher total fat intake, and limited evidence for lower fruit intake, and lower quality diets. Evidence also suggests that short sleepers may have irregular eating behavior deviating from the traditional 3 meals/d to fewer main meals and more frequent, smaller, energy-dense, and highly palatable snacks at night. Although the impact of short sleep duration on dietary intake tends to be small, if chronic, it may contribute to an increased risk of obesity and related chronic disease. Mechanisms mediating the associations between sleep duration and dietary intake are likely to be multifactorial and include differences in the appetite-related hormones leptin and ghrelin, hedonic pathways, extended hours for intake, and altered time of intake. Taking into account these epidemiologic relations and the evidence for causal relations between sleep loss and metabolism and cardiovascular function, health promotion strategies should emphasize improved sleep as an additional factor in health and weight management. Moreover, future sleep interventions in controlled studies and sleep extension trials in chronic short sleepers are imperative for establishing whether there is a causal relation between short sleep duration and changes in dietary intake.
22Role of sleep and sleep loss in hormonal release and metabolism.PubMed
Rachel Leproult, Eve Van Cauter
Endocr Dev. 2010;17:11-21. doi: 10.1159/000262524. Epub 2009 Nov 24.
Compared to a few decades ago, adults, as well as children, sleep less. Sleeping as little as possible is often seen as an admirable behavior in contemporary society. However, sleep plays a major role in neuroendocrine function and glucose metabolism. Evidence that the curtailment of sleep duration may have adverse health effects has emerged in the past 10 years. Accumulating evidence from both epidemiologic studies and well-controlled laboratory studies indicates that chronic partial sleep loss may increase the risk of obesity and weight gain. The present chapter reviews epidemiologic studies in adults and children and laboratory studies in young adults indicating that sleep restriction results in metabolic and endocrine alterations, including decreased glucose tolerance, decreased insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin and increased hunger and appetite. Altogether, the evidence points to a possible role of decreased sleep duration in the current epidemic of obesity. Bedtime extension in short sleepers should be explored as a novel behavioral intervention that may prevent weight gain or facilitate weight loss. Avoiding sleep deprivation may help to prevent the development of obesity, particularly in children.
23Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index.PubMed
Shahrad Taheri, Ling Lin, Diane Austin, et al.
PLoS Med. 2004 Dec;1(3):e62. doi: 10.1371/journal.pmed.0010062. Epub 2004 Dec 7.
BACKGROUND: Sleep duration may be an important regulator of body weight and metabolism. An association between short habitual sleep time and increased body mass index (BMI) has been reported in large population samples. The potential role of metabolic hormones in this association is unknown. METHODS AND FINDINGS: Study participants were 1,024 volunteers from the Wisconsin Sleep Cohort Study, a population-based longitudinal study of sleep disorders. Participants underwent nocturnal polysomnography and reported on their sleep habits through questionnaires and sleep diaries. Following polysomnography, morning, fasted blood samples were evaluated for serum leptin and ghrelin (two key opposing hormones in appetite regulation), adiponectin, insulin, glucose, and lipid profile. Relationships among these measures, BMI, and sleep duration (habitual and immediately prior to blood sampling) were examined using multiple variable regressions with control for confounding factors. A U-shaped curvilinear association between sleep duration and BMI was observed. In persons sleeping less than 8 h (74.4% of the sample), increased BMI was proportional to decreased sleep. Short sleep was associated with low leptin (p for slope = 0.01), with a predicted 15.5% lower leptin for habitual sleep of 5 h versus 8 h, and high ghrelin (p for slope = 0.008), with a predicted 14.9% higher ghrelin for nocturnal (polysomnographic) sleep of 5 h versus 8 h, independent of BMI. CONCLUSION: Participants with short sleep had reduced leptin and elevated ghrelin. These differences in leptin and ghrelin are likely to increase appetite, possibly explaining the increased BMI observed with short sleep duration. In Western societies, where chronic sleep restriction is common and food is widely available, changes in appetite regulatory hormones with sleep curtailment may contribute to obesity.
24How do associations between sleep duration and metabolic health differ with age in the UK general population?PubMed
Anmol Arora, David Pell, Esther M F van Sluijs, et al.
PLoS One. 2020 Nov 23;15(11):e0242852. doi: 10.1371/journal.pone.0242852. eCollection 2020.
BACKGROUND: Despite a growing body of evidence suggesting that short sleep duration may be linked to adverse metabolic outcomes, how these associations differ between age groups remains unclear. We use eight years of data from the UK National Diet and Nutritional Survey (NDNS) (2008-2016) to analyse cross-sectional relationships between sleep duration and metabolic risk in participants aged 11-70 years. METHODS: Participants (n = 2008) who provided both metabolic risk and sleep duration data were included. Self-reported sleep duration was standardised by age, to account for differences in age-related sleep requirements. A standardised metabolic risk score was constructed, comprising: waist circumference, blood pressure, serum triglycerides, serum high-density lipoprotein cholesterol, and fasting plasma glucose. Regression models were constructed across four age groups from adolescents to older adults. RESULTS: Overall, decreased sleep duration (hrs) was associated with an increased metabolic risk (standard deviations) with significant quadratic (B:0.028 [95%CI: 0.007, 0.050]) and linear (B:-0.061 [95%CI: -0.111, -0.011]) sleep duration coefficients. When separated by age group, stronger associations were seen among mid-aged adults (36-50y) (quadratic coefficient: 0.038 [95%CI: 0.002, 0.074]) compared to other age groups (e.g. adolescents (11-18y), quadratic coefficient: -0.009 [95%CI: -0.042, 0.025]). An increased difference between weekend and weekday sleep was only associated with increased metabolic risk in adults aged 51-70 years (B:0.18 [95%CI: 0.005, 0.348]). CONCLUSIONS: Our results indicate that sleep duration is linked to adverse metabolic risk and suggest heterogeneity between age groups. Longitudinal studies with larger sample sizes are required to explore long-term effects of abnormal sleep and potential remedial benefits.
25Sleep quality and obesity in young subjects: a meta-analysis.PubMed
Y Fatima, S A R Doi, A A Mamun
Obes Rev. 2016 Nov;17(11):1154-1166. doi: 10.1111/obr.12444. Epub 2016 Jul 15.
OBJECTIVES: To assess the effect of poor sleep quality on Overweight/Obesity (Ow/Ob) in young subjects, and explore if this association is independent of sleep duration. METHODS: Pubmed, EMBASE, and MEDLINE databases were searched for papers on sleep quality and overweight/obesity, focusing on children, adolescents, and young adults. Studies based on subjects with medical/psychological problems or published in languages other than English were excluded. Quality effects model was used to pool studies for meta-analysis. RESULTS: Findings from the systematic review suggest a link between poor sleep quality and Ow/Ob in young subjects. Pooled estimate (from 26,553 subjects) suggest a role of inadequate sleep (including both short duration and poor quality) in Ow/Ob (OR: 1.27 95% CI: 1.05-1.53). Sub-group-analyses suggest considerably higher odds of Ow/Ob (OR = 1.46, 95% CI: 1.24-1.72) in young subjects with poor sleep quality (independent of duration). CONCLUSIONS: Poor sleep quality seems to be associated with Ow/Ob, and some studies indicate this association to be independent of duration. Therefore, considering only sleep duration might not help in disentangling sleep-obesity association. However, this review is mostly composed of cross-sectional studies. Therefore, a causal link or the stability of the sleep quality and Ow/Ob association could not be established.
26Sleep duration, genetic susceptibility, and Alzheimer's disease: a longitudinal UK Biobank-based study.PubMed
Shiqi Yuan, Wen Ma, Rui Yang, et al.
BMC Geriatr. 2022 Aug 2;22(1):638. doi: 10.1186/s12877-022-03298-8.
BACKGROUND: Alzheimer's disease (AD) is the most frequently occurring type of dementia. Concurrently, inadequate sleep has been recognized as a public health epidemic. Notably, genetic and environmental factors are now considered contributors to AD progression. OBJECTIVE: To assess the association between sleep duration, genetic susceptibility, and AD. METHODS AND RESULTS: Based on 483,507 participants from the UK Biobank (UKB) with an average follow-up of 11.3 years, there was a non-linear relationship between AD incidence and sleep duration (P for non-linear < 0.001) by restricted cubic splines (RCS). Sleep duration was categorized into short sleep duration (< 6 h/night), normal sleep duration (6-9 h/night), and long sleep duration (> 9 h/night). No statistically significant interaction was identified between sleep duration and the AD-GRS (Alzheimer's disease genetic risk score, P for interaction = 0.45) using Cox proportional risk model. Compared with the participants who had a low AD-GRS and normal sleep duration, there was associated with a higher risk of AD in participants with a low AD-GRS and long sleep duration (HR = 3.4806; 95% CI 2.0011-6.054, p < 0.001), participants with an intermediate AD-GRS and long sleep duration (HR = 2.0485; 95% CI 1.3491-3.1105, p < 0.001), participants with a high AD-GRS and normal sleep duration (HR = 1.9272; 95% CI 1.5361-2.4176, p < 0.001), and participants with a high AD-GRS and long sleep duration (HR = 5.4548; 95% CI 3.1367-9.4863, p < 0.001).In addition, there was no causal association between AD and sleep duration using Two Sample Mendelian randomization (MR). CONCLUSION: In the UKB population, though there was no causal association between AD and sleep duration analyzed using Two Sample MR, long sleep duration (> 9 h/night) was significantly associated with a higher risk of AD, regardless of high, intermediate or low AD-GRS. Prolonged sleep duration may be one of the clinical predictors of a higher risk of AD.
27Sleep characteristics and risk of Alzheimer's disease: a systematic review and meta-analysis of longitudinal studies.PubMed
Shichan Wang, Xiaoting Zheng, Jingxuan Huang, et al.
J Neurol. 2024 Jul;271(7):3782-3793. doi: 10.1007/s00415-024-12380-7. Epub 2024 Apr 24.
BACKGROUND: Alzheimer's disease (AD) is on the rise in our aging society, making it crucial to identify additional risk factors to mitigate its increasing incidence. This systematic review and meta-analysis aimed to provide updated evidence regarding the association between sleep and AD. METHODS: We conducted a comprehensive search of MEDLINE, EMBASE, and Web of Science databases from inception to July 2023 to identify longitudinal studies. Adjusted relative risks were pooled for each sleep characteristic, and a dose-response analysis was performed specifically for sleep duration. RESULTS: A total of 15,278 records were initially retrieved, and after screening, 35 records were ultimately included in the final analysis. The results showed that insomnia (RR, 1.43; 95%CI, 1.17-1.74), sleep-disordered breathing (RR, 1.22; 95%CI, 1.07-1.39), as well as other sleep problems, including sleep fragmentation and sleep-related movement disorders, were associated with a higher risk of developing AD, while daytime napping or excessive daytime sleepiness (RR, 1.18; 95%CI, 1.00-1.40) only exhibited a trend toward a higher risk of AD development. Furthermore, our analysis revealed a significant association between self-reported sleep problems (RR, 1.34; 95%CI, 1.26-1.42) and the incidence of AD, whereas this association was not observed with sleep problems detected by objective measurements (RR, 1.14; 95%CI, 0.99-1.31). Moreover, both quite short sleep duration (< 4 h) and long duration (> 8 h) were identified as potential risk factors for AD. CONCLUSIONS: Our study found the association between various types of sleep problems and an increased risk of AD development. However, these findings should be further validated through additional objective device-based assessments. Additional investigation is required to establish a definitive causal connection between sleep problems and AD.
28Impact of sleep on the risk of cognitive decline and dementia.PubMed
Adam P Spira, Lenis P Chen-Edinboro, Mark N Wu, et al.
Curr Opin Psychiatry. 2014 Nov;27(6):478-83. doi: 10.1097/YCO.0000000000000106.
PURPOSE OF REVIEW: Trouble falling or staying asleep, poor sleep quality, and short or long sleep duration are gaining attention as potential risk factors for cognitive decline and dementia, including Alzheimer's disease. Sleep-disordered breathing has also been linked to these outcomes. Here, we review recent observational and experimental studies investigating the effect of poor sleep on cognitive outcomes and Alzheimer's disease, and discuss possible mechanisms. RECENT FINDINGS: Observational studies with self-report and objective sleep measures (e.g. wrist actigraphy, polysomnography) support links between disturbed sleep and cognitive decline. Several recently published studies demonstrate associations between sleep variables and measures of Alzheimer's disease pathology, including cerebrospinal fluid measures of Aβ and PET measures of Aβ deposition. In addition, experimental studies suggest that sleep loss alters cerebrospinal fluid Aβ dynamics, decrements in slow-wave sleep may decrease the clearance of Aβ from the brain, and hypoxemia characteristic of sleep-disordered breathing increases Aβ production. SUMMARY: Findings indicate that poor sleep is a risk factor for cognitive decline and Alzheimer's disease. Although mechanisms underlying these associations are not yet clear, healthy sleep appears to play an important role in maintaining brain health with age, and may play a key role in Alzheimer's disease prevention.
29The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation.PubMed
Hans P A Van Dongen, Greg Maislin, Janet M Mullington, et al.
Sleep. 2003 Mar 15;26(2):117-26. doi: 10.1093/sleep/26.2.117.
OBJECTIVES: To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation. DESIGN: The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days. SETTING: Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring. PARTICIPANTS: A total of n = 48 healthy adults (ages 21-38) participated in the experiments. INTERVENTIONS: Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited. RESULTS: Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h). CONCLUSIONS: Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
30The differential effects of sleep deprivation on pain perception in individuals with or without chronic pain: A systematic review and meta-analysis.PubMed
Jeremy R Chang, Siu-Ngor Fu, Xun Li, et al.
Sleep Med Rev. 2022 Dec;66:101695. doi: 10.1016/j.smrv.2022.101695. Epub 2022 Sep 27.
Many experimental sleep deprivation (SD) studies were conducted to clarify the causal relationship between sleep and pain. This systematic review and meta-analysis aimed to update the evidence regarding the effects of different experimental SD paradigms on various pain outcomes. Five databases were searched from their inception to June 2022. Separate random-effects models were used to estimate the pooled effect sizes (ES) of different experimental SD paradigms on various pain outcomes. Thirty-one studies involving 699 healthy individuals and 47 individuals with chronic pain were included. For healthy individuals, limited evidence substantiated that total SD significantly reduced pain threshold and tolerance (ES 0.74-0.95), while moderate evidence supported that partial SD significantly increased spontaneous pain intensity (ES 0.30). Very limited to moderate evidence showed that sleep fragmentation significantly increased peripheral and central sensitization in healthy individuals (ES 0.42-0.79). Further, there was very limited evidence that total or partial SD significantly aggravated spontaneous pain intensity in people with chronic pain. Our results accentuated that different SD paradigms differentially increased subjective pain intensity and worsened peripheral/central pain sensitization in healthy individuals, whereas the corresponding findings in people with chronic pain remain uncertain. Further rigorous studies are warranted to quantify their relationships in clinical populations.
31The influence of blue light on sleep, performance and wellbeing in young adults: A systematic review.PubMed
Marcia Ines Silvani, Robert Werder, Claudio Perret
Front Physiol. 2022 Aug 16;13:943108. doi: 10.3389/fphys.2022.943108. eCollection 2022.
Blue light from electronic devices has a bad reputation. It has a wavelength which may influence our circadian rhythm and cause bad sleep. But there are other aspects of blue light exposure which are often overlooked, for example, it may influence performance and wellbeing. However, few resources summarize its effects systematically. Therefore, the goal of this systematic review was to distil the present evidence on blue light exposure and its influence on sleep, performance and wellbeing and discuss its significance for athletes. The databases that were searched were Cochrane, Embase, Pubmed, Scopus, and Virtual Health Library. The studies included investigated the influence of blue light exposure on either sleep, performance, wellbeing or a combination of those parameters on healthy humans. Quality assessment was done based on the quantitative assessment tool "QualSyst." Summarizing the influence of blue light exposure, the following results were found (expressed as proportion to the number of studies investigating the particular parameter): Fifty percent of studies found tiredness to be decreased. One fifth of studies found sleep quality to be decreased and one third found sleep duration to be decreased. Half of the studies found sleep efficacy to be decreased and slightly less than half found sleep latency to be increased. More than one half of the studies found cognitive performance to be increased. Slightly more than two thirds found alertness to be increased and reaction time to be decreased. Slightly less than half of the studies found wellbeing to be increased. Blue light exposure can positively affect cognitive performance, alertness, and reaction time. This might benefit sports reliant on team-work and decision-making and may help prevent injury. Blue light might also have negative effects such as the decrease in sleep quality and sleep duration, which might worsen an athlete's physical and cognitive performance and recovery. Further research should explore if blue light can improve sleep, performance and wellbeing to significantly benefit athletic performance.
32Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism.PubMed
O Hecmarie Meléndez-Fernández, Jennifer A Liu, Randy J Nelson
Int J Mol Sci. 2023 Feb 8;24(4):3392. doi: 10.3390/ijms24043392.
Availability of artificial light and light-emitting devices have altered human temporal life, allowing 24-hour healthcare, commerce and production, and expanding social life around the clock. However, physiology and behavior that evolved in the context of 24 h solar days are frequently perturbed by exposure to artificial light at night. This is particularly salient in the context of circadian rhythms, the result of endogenous biological clocks with a rhythm of ~24 h. Circadian rhythms govern the temporal features of physiology and behavior, and are set to precisely 24 h primarily by exposure to light during the solar day, though other factors, such as the timing of meals, can also affect circadian rhythms. Circadian rhythms are significantly affected by night shift work because of exposure to nocturnal light, electronic devices, and shifts in the timing of meals. Night shift workers are at increased risk for metabolic disorder, as well as several types of cancer. Others who are exposed to artificial light at night or late mealtimes also show disrupted circadian rhythms and increased metabolic and cardiac disorders. It is imperative to understand how disrupted circadian rhythms alter metabolic function to develop strategies to mitigate their negative effects. In this review, we provide an introduction to circadian rhythms, physiological regulation of homeostasis by the suprachiasmatic nucleus (SCN), and SCN-mediated hormones that display circadian rhythms, including melatonin and glucocorticoids. Next, we discuss circadian-gated physiological processes including sleep and food intake, followed by types of disrupted circadian rhythms and how modern lighting disrupts molecular clock rhythms. Lastly, we identify how disruptions to hormones and metabolism can increase susceptibility to metabolic syndrome and risk for cardiovascular diseases, and discuss various strategies to mitigate the harmful consequences associated with disrupted circadian rhythms on human health.
33The effect of reducing blue light from smartphone screen on subjective quality of sleep among students.PubMed
Pavle Randjelović, Nikola Stojanović, Ivan Ilić, et al.
Chronobiol Int. 2023 Mar;40(3):335-342. doi: 10.1080/07420528.2023.2173606. Epub 2023 Feb 6.
The exposure of humans to artificial light at night (ALAN) with predominant blue part of the visible spectrum is strongly influencing circadian rhythm and sleep through melanopsin-containing retinal ganglion cells (RGC). We hypothesized that reducing the amount of emitted blue light from screens of mobile phones during the night will increase sleep quality in our student population. The aim of the work was to investigate the effect of reducing blue light from smartphone screen during the night on subjective quality of sleep among students of medicine. The target population was students of medicine aged 20 to 22 years old of both sexes. The primary outcome of the study was subjective sleep quality, assessed by the Serbian version of the Pittsburgh Sleep Quality Index (PSQI). The mean total PSQI score before intervention was 6.83 ± 2.73 (bad), while after the intervention the same score was statistically significant reduced to 3.93 ± 1.68 (good) with large effect size. The study has shown that a reduction of blue light emission from LED backlight screens of mobile phones during the night leads to improved subjective quality of sleep in students, as well as improvement in daytime functioning and going to sleep.
34The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: a systematic review of the literature.PubMed
John G Lawrenson, Christopher C Hull, Laura E Downie
Ophthalmic Physiol Opt. 2017 Nov;37(6):644-654. doi: 10.1111/opo.12406.
PURPOSE: Blue-blocking (BB) spectacle lenses, which attenuate short-wavelength light, are being marketed to alleviate eyestrain and discomfort when using digital devices, improve sleep quality and potentially confer protection from retinal phototoxicity. The aim of this review was to investigate the relative benefits and potential harms of these lenses. METHODS: We included randomised controlled trials (RCTs), recruiting adults from the general population, which investigated the effect of BB spectacle lenses on visual performance, symptoms of eyestrain or eye fatigue, changes to macular integrity and subjective sleep quality. We searched MEDLINE, EMBASE, the Cochrane Library and clinical trial registers, until 30 April 2017. Risk of bias was assessed using the Cochrane tool. RESULTS: Three studies (with 136 participants) met our inclusion criteria; these had limitations in study design and/or implementation. One study compared the effect of BB lenses with clear lenses on contrast sensitivity (CS) and colour vision (CV) using a pseudo-RCT crossover design; there was no observed difference between lens types (log CS; Mean Difference (MD) = -0.01 [-0.03, 0.01], CV total error score on 100-hue; MD = 1.30 [-7.84, 10.44]). Another study measured critical fusion frequency (CFF), as a proxy for eye fatigue, on wearers of low and high BB lenses, pre- and post- a two-hour computer task. There was no observed difference between low BB and standard lens groups, but there was a less negative change in CFF between the high and low BB groups (MD = 1.81 [0.57, 3.05]). Both studies compared eyestrain symptoms with Likert scales. There was no evidence of inter-group differences for either low BB (MD = 0.00 [-0.22, 0.22]) or high BB lenses (MD = -0.05 [-0.31, 0.21]), nor evidence of a difference in the proportion of participants showing an improvement in symptoms of eyestrain or eye fatigue. One study reported a small improvement in sleep quality in people with self-reported insomnia after wearing high compared to low-BB lenses (MD = 0.80 [0.17, 1.43]) using a 10-point Likert scale. A study involving normal participants found no observed difference in sleep quality. We found no studies investigating effects on macular structure or function. CONCLUSIONS: We find a lack of high quality evidence to support using BB spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.
35Do blue light filter applications improve sleep outcomes? A study of smartphone users' sleep quality in an observational setting.PubMed
Marziye Rabiei, Seyed Jalil Masoumi, Masoud Haghani, et al.
Electromagn Biol Med. 2024 Apr 2;43(1-2):107-116. doi: 10.1080/15368378.2024.2327432. Epub 2024 Mar 10.
Exposure to blue light at bedtime, suppresses melatonin secretion, postponing the sleep onset and interrupting the sleep process. Some smartphone manufacturers have introduced night-mode functions, which have been claimed to aid in improving sleep quality. In this study, we evaluate the impact of blue light filter application on decreasing blue light emissions and improving sleep quality. Participants in this study recorded the pattern of using their mobile phones through a questionnaire. In order to evaluate sleep quality, we used a PSQI questionnaire. Blue light filters were used by 9.7% of respondents, 9.7% occasionally, and 80% never. The mean score of PSQI was more than 5 in 54.10% of the participants and less than 5 in 45.90%. ANOVA test was performed to assess the relationship between using blue light filter applications and sleep quality (p-value = 0.925). The findings of this study indicate a connection between the use of blue light filter apps and habitual sleep efficiency in the 31-40 age group. However, our results align only to some extent with prior research, as we did not observe sustained positive effects on all parameters of sleep quality from the long-term use of blue light filtering apps. Several studies have found that blue light exposure can suppress melatonin secretion, exacerbating sleep problems. Some studies have reported that physical blue light filters, such as lenses, can affect melatonin secretion and improve sleep quality. However, the impact of blue light filtering applications remains unclear and debatable.
36Circadian rhythms and meal timing: impact on energy balance and body weight.PubMed
Hedda L Boege, Mehreen Z Bhatti, Marie-Pierre St-Onge
Curr Opin Biotechnol. 2021 Aug;70:1-6. doi: 10.1016/j.copbio.2020.08.009. Epub 2020 Sep 29.
Energy metabolism and appetite regulating hormones follow circadian rhythms which, when disrupted, could lead to adverse metabolic consequences. Such circadian misalignment, a mismatch between endogenous circadian rhythms and behavior, is most severely experienced by shift workers, due to nighttime wake, daytime sleep, and eating at night. However, circadian misalignment is not restricted to shift workers; milder shifts in sleep and mealtimes, termed social and eating jetlag, are highly prevalent in the general population. Social and eating jetlag result in later mealtimes, which may promote positive energy balance and weight gain. Earlier meal timing, specific to individual endogenous circadian patterns, could serve to reduce cardiometabolic disease burden and aid in weight loss and interventions should be done to test this.
37Alcohol and the sleeping brain.PubMed
Ian M Colrain, Christian L Nicholas, Fiona C Baker
Handb Clin Neurol. 2014;125:415-31. doi: 10.1016/B978-0-444-62619-6.00024-0.
Alcohol acts as a sedative that interacts with several neurotransmitter systems important in the regulation of sleep. Acute administration of large amounts of alcohol prior to sleep leads to decreased sleep-onset latency and changes in sleep architecture early in the night, when blood alcohol levels are high, with subsequent disrupted, poor-quality sleep later in the night. Alcohol abuse and dependence are associated with chronic sleep disturbance, lower slow-wave sleep, and more rapid-eye-movement sleep than normal, that last long into periods of abstinence and may play a role in relapse. This chapter outlines the evidence for acute and chronic alcohol effects on sleep architecture and sleep electroencephalogram, evidence for tolerance with repeated administration, and possible underlying neurochemical mechanisms for alcohol's effects on sleep. Also discussed are sex differences as well as effects of alcohol on sleep homeostasis and circadian regulation. Evidence for the role of sleep disruption as a risk factor for developing alcohol dependence is discussed in the context of research conducted in adolescents. The utility of sleep-evoked potentials in the assessment of the effects of alcoholism on sleep and the brain and in abstinence-mediated recovery is also outlined. The chapter concludes with a series of questions that need to be answered to determine the role of sleep and sleep disturbance in the development and maintenance of problem drinking and the potential beneficial effects of the treatment of sleep disorders for maintenance of abstinence in alcoholism.
38Alcohol and sleep-related problems.PubMed
Sean He, Brant P Hasler, Subhajit Chakravorty
Curr Opin Psychol. 2019 Dec;30:117-122. doi: 10.1016/j.copsyc.2019.03.007. Epub 2019 Apr 19.
Alcohol is one of the most commonly used psychoactive substances in the community. Many individuals use alcohol for its sleep-promoting effects. Nonetheless, alcohol disrupts sleep through multiple mechanisms, such as disrupting electrophysiologic sleep architecture, triggering insomnia, and contributing to abnormalities of circadian rhythms and short sleep duration (SSD) in cross-sectional studies. Alcohol also increases breathing-related sleep events such as snoring and oxygen desaturation, especially in those with pre-existing problems. Emerging data demonstrate that insomnia may co-exist with SSD and circadian abnormalities. Future studies should unravel these tentative associations in individuals who misuse alcohol.
39Association between alcohol consumption and sleep traits: observational and mendelian randomization studies in the UK biobank.PubMed
Jun-Wei Zheng, Si-Zhi Ai, Su-Hua Chang, et al.
Mol Psychiatry. 2024 Mar;29(3):838-846. doi: 10.1038/s41380-023-02375-7. Epub 2024 Jan 18.
Previous studies have shown that excessive alcohol consumption is associated with poor sleep. However, the health risks of light-to-moderate alcohol consumption in relation to sleep traits (e.g., insomnia, snoring, sleep duration and chronotype) remain undefined, and their causality is still unclear in the general population. To identify the association between alcohol consumption and multiple sleep traits using an observational and Mendelian randomization (MR) design. Observational analyses and one-sample MR (linear and nonlinear) were performed using clinical and individual-level genetic data from the UK Biobank (UKB). Two-sample MR was assessed using summary data from genome-wide association studies from the UKB and other external consortia. Phenotype analyses were externally validated using data from the National Health and Nutrition Examination Survey (2017-2018). Data analysis was conducted from January 2022 to October 2022. The association between alcohol consumption and six self-reported sleep traits (short sleep duration, long sleep duration, chronotype, snoring, waking up in the morning, and insomnia) were analysed. This study included 383,357 UKB participants (mean [SD] age, 57.0 [8.0] years; 46% male) who consumed a mean (SD) of 9.0 (10.0) standard drinks (one standard drink equivalent to 14 g of alcohol) per week. In the observational analyses, alcohol consumption was significantly associated with all sleep traits. Light-moderate-heavy alcohol consumption was linearly linked to snoring and the evening chronotype but nonlinearly associated with insomnia, sleep duration, and napping. In linear MR analyses, a 1-SD (14 g) increase in genetically predicted alcohol consumption was associated with a 1.14-fold (95% CI, 1.07-1.22) higher risk of snoring (P < 0.001), a 1.28-fold (95% CI, 1.20-1.37) higher risk of evening chronotype (P < 0.001) and a 1.24-fold (95% CI, 1.13-1.36) higher risk of difficulty waking up in the morning (P < 0.001). Nonlinear MR analyses did not reveal significant results after Bonferroni adjustment. The results of the two-sample MR analyses were consistent with those of the one-sample MR analyses, but with a slightly attenuated overall estimate. Our findings suggest that even low levels of alcohol consumption may affect sleep health, particularly by increasing the risk of snoring and evening chronotypes. The negative effects of alcohol consumption on sleep should be made clear to the public in order to promote public health.
40Time-restricted Eating for the Prevention and Management of Metabolic Diseases.PubMed
Emily N C Manoogian, Lisa S Chow, Pam R Taub, et al.
Endocr Rev. 2022 Mar 9;43(2):405-436. doi: 10.1210/endrev/bnab027.
Time-restricted feeding (TRF, animal-based studies) and time-restricted eating (TRE, humans) are an emerging behavioral intervention approach based on the understanding of the role of circadian rhythms in physiology and metabolism. In this approach, all calorie intake is restricted within a consistent interval of less than 12 hours without overtly attempting to reduce calories. This article will summarize the origin of TRF/TRE starting with concept of circadian rhythms and the role of chronic circadian rhythm disruption in increasing the risk for chronic metabolic diseases. Circadian rhythms are usually perceived as the sleep-wake cycle and dependent rhythms arising from the central nervous system. However, the recent discovery of circadian rhythms in peripheral organs and the plasticity of these rhythms in response to changes in nutrition availability raised the possibility that adopting a consistent daily short window of feeding can sustain robust circadian rhythm. Preclinical animal studies have demonstrated proof of concept and identified potential mechanisms driving TRF-related benefits. Pilot human intervention studies have reported promising results in reducing the risk for obesity, diabetes, and cardiovascular diseases. Epidemiological studies have indicated that maintaining a consistent long overnight fast, which is similar to TRE, can significantly reduce risks for chronic diseases. Despite these early successes, more clinical and mechanistic studies are needed to implement TRE alone or as adjuvant lifestyle intervention for the prevention and management of chronic metabolic diseases.
41Circadian Rhythm Sleep-Wake Disorders.PubMed
Milena Pavlova
Continuum (Minneap Minn). 2017 Aug;23(4, Sleep Neurology):1051-1063. doi: 10.1212/CON.0000000000000499.
PURPOSE OF REVIEW: The endogenous circadian rhythms are one of the cardinal processes that control sleep. They are self-sustaining biological rhythms with a periodicity of approximately 24 hours that may be entrained by external zeitgebers (German for time givers), such as light, exercise, and meal times. This article discusses the physiology of the circadian rhythms, their relationship to neurologic disease, and the presentation and treatment of circadian rhythm sleep-wake disorders. RECENT FINDINGS: Classic examples of circadian rhythms include cortisol and melatonin secretion, body temperature, and urine volume. More recently, the impact of circadian rhythm on several neurologic disorders has been investigated, such as the timing of occurrence of epileptic seizures as well as neurobehavioral functioning in dementia. Further updates include a more in-depth understanding of the symptoms, consequences, and treatment of circadian sleep-wake disorders, which may occur because of extrinsic misalignment with clock time or because of intrinsic dysfunction of the brain. An example of extrinsic misalignment occurs with jet lag during transmeridian travel or with intrinsic circadian rhythm sleep-wake disorders such as advanced or delayed sleep-wake phase disorders. In advanced sleep-wake phase disorder, which is most common in elderly individuals, sleep onset and morning arousal are undesirably early, leading to impaired evening function with excessive sleepiness and sleep-maintenance insomnia with early morning awakening. By contrast, delayed sleep-wake phase disorder is characterized by an inability to initiate sleep before the early morning hours, with subsequent delayed rise time, leading to clinical symptoms of severe sleep-onset insomnia coupled with excessive daytime sleepiness in the morning hours, as patients are unable to "sleep in" to attain sufficient sleep quantity. Irregular sleep-wake rhythm disorder is misentrainment with patches of brief sleep and wakefulness spread throughout the day, leading to unstable sleep and waking behavioral patterns and an entirely idiosyncratic sleep-wake schedule. SUMMARY: Familiarity with these major circadian rhythm sleep-wake disorder phenotypes and their overlap with other neurologic disorders is essential for the neurologist so that clinicians may intervene and improve patient functioning and quality of life.
42Hypothalamic DysfunctionPubMed
Jose G. Sanchez Jimenez, Orlando De Jesus
The hypothalamus is a part of the diencephalon composed of several small nuclei that have different physiologic functions. One of the main functions of the hypothalamus is to maintain homeostasis by controlling the endocrine and autonomic functions; nevertheless, it participates in other functions such as body temperature regulation, appetite, and weight, childbirth, growth, breast milk production, sleep-wake cycle, sex drive, emotions, and behavior. A disorder of the hypothalamus can cause different signs and symptoms, depending on the particular affected area. Clinical manifestations vary, depending on the affected hypothalamic nuclei and their functions. Certain signs and symptoms can be traced to a specific anatomic area because of this functional organization within the hypothalamus. Anatomically, this structure can be organized in the sagittal plane into three main regions: the anterior, middle, and posterior. Each main region contains hypothalamic nuclei that serve different physiologic functions. The anterior region contains five nuclei: preoptic, paraventricular, supraoptic, suprachiasmatic, and anterior hypothalamic nucleus. The middle region of the hypothalamus is situated directly above the tuber cinereum and the infundibulum and contains three nuclei: the arcuate nucleus, ventromedial nucleus, and dorsomedial nucleus. The posterior region contains the posterior hypothalamic nucleus and the mammillary nucleus in the mammillary bodies. the primary function is the production and secretion of gonadotropin-releasing hormone (GnRH) for sex hormone regulation. GnRH is released into the tuberoinfundibular tract and is transported through the hypophyseal portal system to the adenohypophysis. This nucleus also participates in initiating non-rapid eye movement sleep via the inhibition of histaminergic neurons in the hypothalamus and cholinergic and noradrenergic neurons in the brainstem. It also is involved in thermoregulation. participates in the production and secretion of several hormones, predominantly oxytocin. It also produces and secretes small amounts of vasopressin, also called antidiuretic hormone (ADH). Another hormone produced is a corticotropin-releasing hormone (CRH), which regulates adrenocorticotropin hormone secretion by the anterior pituitary. It also produces thyroid releasing hormone (TRH), which will control hormonal secretion by the thyroid. This nucleus contains glutamate and AngII-releasing neurons, which induce sympatho-excitatory effects, whereas gamma-aminobutyric acid and nitric oxide-releasing neurons induce sympatho-inhibitory effects. These sympathetic effects, when deregulated, have some influence on heart failure. its secretory functions are similar to the paraventricular nucleus, but its primary function is the production and secretion of vasopressin. This nucleus also produces and secretes oxytocin to a lesser degree than the paraventricular nucleus. this nucleus receives direct input from retinal ganglion cells and synchronized body functions with periods of light and dark to a circadian rhythm. It projects to the pineal gland, which secretes the hormone melatonin, a sleep-inducing hormone. it controls body temperatures, and its function includes cooling or reducing the body temperature. this nucleus releases growth hormone-releasing hormone (GHRH) and produces prolactin-inhibiting hormone (dopamine). this is the center of satiety or fullness. this is an emotional response center. Stimulation of this nucleus, in animal experiments, produced aggressive behavior that lasts only as long as the stimulus is applied. It is also involved with blood pressure, heart rate, and gastrointestinal stimulation. this nucleus is part of the limbic system, a system that is responsible for memory, behavior, motivation, and motivation. Degeneration of this nucleus classically occurs in Korsakoff syndrome. It is involved in memory, changes in emotion, and heart failure. this region participates in blood pressure regulation, pupillary dilation, and thermoregulation, particularly body temperature conservation, such as shivering when a person is cold.
43Melatonin, cortisol and body temperature rhythms in Lennox-Gastaut patients with or without circadian rhythm sleep disorders.PubMed
M L Laakso, L Leinonen, T Hätönen, et al.
J Neurol. 1993 Jul;240(7):410-6. doi: 10.1007/BF00867353.
The daily rhythms of melatonin, cortisol and body temperature were studied in 16 institutionalized subjects with the Lennox-Gastaut syndrome. The results of 9 subjects with normal daily rhythms of sleep and wakefulness (group 1) were compared with those of 7 subjects with disordered sleep (group 2). Salivary samples were collected and axillary temperature was measured every 2 h during two or three separate 26-h periods. The hormones were measured by radioimmunoassays. The rhythms were characterized with single cosinor analysis. Two subjects in group 1 and six subjects in group 2 had abnormalities in their rhythms of temperature, cortisol or melatonin. All three rhythms were disrupted in two subjects of group 2. These two subjects were the only ones with disrupted cortisol rhythm. The diversity of rhythm pathologies suggested partly separate regulatory mechanisms for each rhythm. The co-occurrence of circadian rhythm sleep disorders with the deteriorated melatonin rhythm raised the question as to whether the sleep disorders of these subjects, like those of subjects with healthy brains, could be relieved by the induction of normal melatonin rhythm.
44Regularity of bedtime, wake-up time, and time in bed in mid-life: associations with cardiometabolic health markers with adjustment for physical activity and sedentary time.PubMed
Laura Nauha, Vahid Farrahi, Heidi Jurvelin, et al.
J Act Sedentary Sleep Behav. 2024 Jan 5;3(1):2. doi: 10.1186/s44167-023-00040-6.
BACKGROUND: Insufficient sleep has been linked to the accumulation of cardiometabolic risks while physical activity acts as a protective factor. Also, sleep regularity may play a critical role in maintaining optimal cardiometabolic health. This cross-sectional study examined the association between device-based sleep regularity, waking activity behaviors, and cardiometabolic health markers, including blood pressure level; abdominal adiposity level; and blood glucose, insulin, and cholesterol. METHODS: We included 3698 members of the Northern Finland Birth cohort 1966 who participated in the follow-up study at the age of 46 years between 2012 and 2014 (women 61%). We used seven-day standard deviations of device-based bedtime, wake-up time, and time in bed to reflect sleep regularities. As covariates in linear regression models, we used commonly known potential risk factors in (gender, education, marital status, work schedule, smoking status, alcohol risk use, seven-day time in bed mean, chronotype). In addition to the previous, we used either sedentary time or total physical activity as a covariate (B coefficients with 95% confidence intervals CI). RESULTS: When we considered sedentary time with other covariates, irregularities in bedtime, wake-up time, and time in bed were associated with unfavorable cardiometabolic health markers, such as higher body mass index (bedtime regularity: 0.194, 95% CI [0.072, 0.316], p = 0.002); higher diastolic blood pressure levels (time in bed regularity: 0.175, 95% CI [0.044, 0.306], p = 0.009); and higher 2-h glucose levels (wake-up time regularity: 0.107, 95% CI [0.030, 0.184], p = 0.006). When we considered total physical activity with other covariates, only irregular bedtime was associated with higher waist circumference (B 0.199, 95% CI [0.042, 0.356], p = 0.013). Irregularities in bedtime and wake-up time were not associated with higher diastolic blood pressure, higher visceral fat area or higher fasting insulin level after considering sedentary time or total physical activity with other covariates (in all, p > 0.05). CONCLUSIONS: In middle-aged, physical activity appears to weaken the adverse relationship between irregular sleep and cardiometabolic health markers, although the interpretation of the impact of sedentary time remains less conclusive. The clinical significance and extent of the observed associations warrant further investigation.
45The thermophysiological cascade leading to sleep initiation in relation to phase of entrainment.PubMed
Kurt Kräuchi
Sleep Med Rev. 2007 Dec;11(6):439-51. doi: 10.1016/j.smrv.2007.07.001. Epub 2007 Aug 30.
This article reviews circadian thermoregulation in relation to sleep induction and phase of entrainment in the light of the comprehensive thermophysiological and chronobiological concepts of Jürgen Aschoff. The idea that temperature and sleep are interrelated is based on evolutionary history. Mammalian sleep developed in association with endothermy, and all species, independent of temporal niche, usually sleep during the circadian trough of their core body temperature (CBT) rhythm. The circadian pattern of CBT results from the balance between heat production and heat loss, the latter being relevant for sleep induction. Sleep under entrained conditions is typically initiated on the declining portion of the CBT curve when its rate of change and body heat loss is maximal. Body heat loss before lights off, via selective vasodilatation of distal skin regions, promotes sleepiness and the rapid onset of sleep. This thermophysiological effect represents the cement between the circadian clock and the sleep-wake cycle, and in turn determines phase of entrainment (Psi) and sleep onset latency (SOL). These interrelationships have been recently studied in a particular subset of the general population, mainly women, who suffer from cold hands and feet (the so-called vasospastic syndrome, VS). Women with VS exhibit not only a lower capacity to lose heat during the daytime but also a prolonged SOL, a disturbed Psi of the circadian clock with respect to the sleep-wake cycle and psychologically, a disposition to turn experienced anger inwards. This naturalistic model leads us to a more general conclusion that regulation of distal skin blood flow may have clinical relevance for insomnia, in particular sleep onset insomnia.
46Sleep and thermoregulation.PubMed
Edward C Harding, Nicholas P Franks, William Wisden
Curr Opin Physiol. 2020 Jun;15:7-13. doi: 10.1016/j.cophys.2019.11.008.
In homeothermic animals sleep preparatory behaviours often promote thermal efficiency, including warmth-seeking, adopting particular postures (curling up, head tucking) and nest building, all promoting warmer skin microclimates. Skin warmth induces NREM sleep and body cooling via circuitry that connects skin sensation to the preoptic hypothalamus. Coupling sleep induction and lower body temperature could serve to minimise energy expenditure or allow energy reallocation. Cooling during NREM sleep may also induce transcriptional changes in genes whose products facilitate housekeeping functions or measure the time spent sleeping.
47[Sleep and Body Temperature].PubMed
Asuka Ishihara, Insung Park, Kumpei Tokuyama
Brain Nerve. 2022 Feb;74(2):173-178. doi: 10.11477/mf.1416202003.
Mammals and birds seek a warm environment prior to sleep, which triggers vasodilatation and body cooling. Ambient temperatures outside the thermoneutral zone suppress sleep, particularly rapid eye movement (REM) sleep. We discuss the neurocircuit interactions associated with thermal and sleep regulation that occur primarily in the hypothalamic areas. An increase in ambient temperature stimulates the median preoptic/medial preoptic area of the hypothalamus, decreases body temperature, and increases non-REM sleep. Similarly, optical stimulation of the ventrolateral preoptic nucleus, which contains galanin (VLPO), results in body cooling and non-REM sleep. A decrease in VLPO disrupts sleep in elderly individuals and may also be associated with reduced decline in core body temperature during sleep. However, stimulation of neurons that synthesize melanin-concentrating hormone in the lateral hypothalamus decreases body temperature and induces REM sleep. We also discussed the acute effect of light on sleep induction and decreased body temperature, implicated with gamma-aminobutyric acid-ergic neurons in the preoptic area. Further investigation is needed to determine the mechanisms that induce physiological responses in diurnal and nocturnal species. These studies will contribute to a better understanding of the association between sleep and thermoregulation.
48Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults.PubMed
Timothy M Brown, George C Brainard, Christian Cajochen, et al.
PLoS Biol. 2022 Mar 17;20(3):e3001571. doi: 10.1371/journal.pbio.3001571. eCollection 2022 Mar.
Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly developed, international standard provides a SI-compliant way of quantifying the influence of light on the intrinsically photosensitive, melanopsin-expressing, retinal neurons that mediate these effects. The present report provides recommendations for lighting, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard. The recommendations are supported by detailed analysis of the sensitivity of human circadian, neuroendocrine, and alerting responses to ocular light and provide a straightforward framework to inform lighting design and practice.
49Noise as a sleep aid: A systematic review.PubMed
Samantha M Riedy, Michael G Smith, Sarah Rocha, et al.
Sleep Med Rev. 2021 Feb;55:101385. doi: 10.1016/j.smrv.2020.101385. Epub 2020 Sep 9.
White noise is purported to mask disruptive noises in the bedroom environment and be a non-pharmacological approach for promoting sleep and improving sleep quality. We conducted a systematic review of all studies examining the relationships between continuous white noise or similar broadband noise and sleep (PROSPERO 2020: CRD42020148736). Animal studies and studies using intermittent white noise to disrupt sleep or enhance slow wave activity were excluded. Two reviewers independently screened titles and abstracts of articles from three databases and assessed risk of bias for the 38 included articles. The primary outcomes described sleep onset latency, sleep fragmentation, sleep quality, and sleep and wake duration. There was heterogeneity in noise characteristics, sleep measurement methodology, adherence to the intervention, control group conditions or interventions, and presence of simultaneous experimental interventions. There was perhaps resultantly variability in research findings, with the extremes being that continuous noise improves or disrupts sleep. Following the GRADE criteria, the quality of evidence for continuous noise improving sleep was very low, which contradicts its widespread use. Additional research with objective sleep measures and detailed descriptions of noise exposure is needed before promoting continuous noise as a sleep aid, especially since it may also negatively affect sleep and hearing.
50Applications of White Noise in Maternal and Neonatal Care: A Comprehensive Review on Sleep, Stress, and Pain Outcomes.PubMed
Tuğba Öz, Nurdan Demirci
Noise Health. 2025;27(129):668-675. doi: 10.4103/nah.nah_154_25. Epub 2025 Dec 31.
This review aimed to systematically synthesize the current literature on the physiological and psychological effects of white noise on sleep quality, stress levels, and pain perception in both mothers and newborns. The primary objective was to critically examine existing evidence on the use of white noise in maternal and neonatal care interventions. A comprehensive literature search was conducted across major electronic databases, including PubMed, Web of Science, and Scopus, using keywords such as "white noise," "sleep," "stress," and "pain." After screening titles, abstracts, and full texts according to the selection criteria, 12 articles were selected for critical review. Findings from randomized controlled trials (RCTs) consistently indicate that white noise can shorten sleep latency, improve sleep onset, and reduce pain perception in both mothers and newborns. Additional randomized studies demonstrated benefits for physiological indicators, such as heart rate variability and oxygen saturation, particularly in neonatal intensive care settings. In contrast, evidence from reviews and expert opinions highlights potential risks associated with prolonged or high-intensity white noise exposure, including possible hearing impairment, negative impacts on cognitive functions, and neurodevelopmental delays. These differences highlight the importance of interpreting findings in light of the study design and methodological rigor. White noise presents itself as a practical, low-cost, non-invasive, and easily implementable method for improving maternal and neonatal care outcomes, particularly in sleep, stress, and pain management, provided it is applied within safe sound levels. Nevertheless, its effectiveness may vary across individuals and contexts. Future directions should focus on large-sample, long-term RCTs to establish definitive evidence and to differentiate between short-term benefits and potential long-term harms. The development of standardized protocols with evidence-based safety thresholds will be crucial in maximizing therapeutic benefits while minimizing risks.
51The effects of white noise on sleep and duration in individuals living in a high noise environment in New York City.PubMed
Matthew R Ebben, Peter Yan, Ana C Krieger
Sleep Med. 2021 Jul;83:256-259. doi: 10.1016/j.sleep.2021.03.031. Epub 2021 Apr 6.
INTRODUCTION: Undisturbed sleep has been shown to be important for both health and quality of life (Medic et al. [7]). The World Health Organization estimates that nearly 25% of the population suffers from disturbed sleep due to environmental noise (Health TWECfEa, [2]). Sleep disturbance associated with elevated noise levels is particularly prevalent in metropolitan areas. Our study tested the hypothesis that white noise would improve sleep in New Yorkers complaining of sleep difficulty due to elevated sound levels. METHODS: Ten adult participants were included in this study. All participants were recruited from a New York City based sleep clinic. Inclusion criteria was based on the presence of sleep disturbance and the reporting of high levels of environmental noise in participants' sleep location. The study was conducted using a within-subject, ABA design, with baseline, treatment phase, followed by another baseline (washout) period. Each phase lasted one-week, during which noise level and sleep were assessed. The treatment consisted of the application of a white noise device (Dohm Classic by Marpac, LLC) in the participants' bedroom. Sleep parameters were measured subjectively using the Consensus Sleep Diary (Carney et al. [15]), and objectively using a Motionlogger Actigraph. RESULTS: Paired sample t-tests were conducted to evaluate the hypothesis that white noise improves sleep in a high noise environment. Significance was found on the variables WASO, as measured by actigraphy, t(9) = 3.438, p = 0.007 and sleep latency as measured by sleep diary, t(9) = 2.947, p = 0.016. There was a trend toward significance on the number of awakenings during the night, as measured by sleep diary, t(9) = 2.622, p = 0.028 (Holm's sequential correction of p-value required a value of <0.01 to find significance on this comparison) and sleep efficiency (actigraph), t(9) = -2.121, p = 0.063. CONCLUSION: Our data show that white noise significantly improved sleep based on subjective and objective measurements in subjects complaining of difficulty sleeping due to high levels of environmental noise. This suggests that the application of white noise may be an effective tool in helping to improve sleep in those settings.
52Impact and efficacy of sound machine on sleep in hospitalized adults: A systematic review.PubMed
Kanika Khandelwal, Alecia Anyim, Sara Shu, et al.
Sleep Med X. 2025 Sep 29;10:100154. doi: 10.1016/j.sleepx.2025.100154. eCollection 2025 Dec 15.
BACKGROUND: Sleep in hospitalized adults is impaired due to several reasons. Non-pharmacological approaches should be attempted first before considering medications to treat insomnia. Environmental noise levels in the hospital are also a major culprit that might result in disturbed sleep. While limiting any disturbance or sound during sleeping hours is crucial, it might not be completely feasible in the acute care setting. Sound machines that deliver a masking noise such as white noise are reported to mask these environmental noises and promote sleep. We aim to analyze the efficacy and safety of sound machines on sleep efficiency in hospitalized adults. METHODS: A systematic review of all published literature was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched MEDLINE, Embase, Cochrane Cochrane Central Register of Controlled Trials, EBSCO CINAHL, Google scholar, APA PsycINFO, Web of Science, and Scopus from inception to August 13, 2024. All studies that reported sound machine-based interventions on sleep efficiency in hospitalized adults were included. Sleep efficiency and other sleep related outcomes as total sleep time, latency, awakenings, and total sleep score were noted. Cochrane Risk of Bias 2 for RCTs was used to evaluate study quality. This study was registered with PROSPERO (CRD42024595293). RESULTS: A total of 1920 studies were screened, of which 74 were selected for full text review. Seven RCT studies ( = 496 participants) met the inclusion criteria and were included. Two studies were from USA, and India each, while one study was reported each from Iran, China, and South Korea. Six of the seven studies used white noise, while one study reported using Uncorrelated Signal and Ambient noise in Space Integration (USASI) masking noise. Two studies reported using Pittsburgh Sleep Quality Index (PSQI), and Richards Campbell Sleep Questionnaire (RCSQ) each to measure sleep outcomes. White noise was well tolerated with no major adverse effects reported, and only 8 participants discontinued the study due to discomfort or found it less acceptable. Collectively, these studies provide evidence of improved sleep efficiency with white noise use in hospitalized adults. Given the heterogeneity in the duration of white noise use, inclusion criteria, and the outcome measurement scales in this small sample of RCT studies, meta-analysis was not feasible. CONCLUSIONS: White-noise and other similar masking noises seem to improve sleep efficiency in hospitalized adults, with good tolerability. Only limited studies report the efficacy and demonstrate wide heterogeneity in the duration of masking noise use, varied inclusion criteria, and outcome measurement scales. Larger studies analyzing the hospitalized patient population type, across different units, to identify the best patient population who would benefit from these masking sounds are needed.
53The crying baby.PubMed
Harriet Hiscock
Aust Fam Physician. 2006 Sep;35(9):680-4.
BACKGROUND: Up to 20% of parents report a problem with their infant crying in the first 3 months of life. The majority of babies have no organic cause of crying and most crying subsides by 3-4 months. OBJECTIVE: This article describes the management of persistent crying in the first 3 months of life. DISCUSSION: Management includes exclusion of medical causes and ensuring the baby is adequately rested and fed. Unexplained episodes of crying can be managed by: carrying the baby, going for a walk with baby in the pram, giving baby a deep, warm bath, or playing white noise or environmental sounds to distract the baby from crying. Postnatal depression is common in mothers of crying babies and should be actively screened for and appropriate clinical help offered if required. All families benefit from support including a review appointment and practical help around the home where possible.
54Challenges and suggestions for the assessment and treatment of bedtime problems and night wakings in children under six.PubMed
Guang-Hai Wang, Yu-Jiao Deng, Meng-Fei Zhou, et al.
World J Pediatr. 2025 Nov;21(11):1070-1080. doi: 10.1007/s12519-025-00985-5. Epub 2025 Oct 30.
BACKGROUND: Bedtime problems and night wakings are common in children under six, particularly in China. The current study summarizes the core tenets of the "Chinese guideline for the treatment of bedtime problems and night wakings in children under 6 years of age (2023)", and discusses the associated challenges and suggestions for practices relevant to both domestic and international contexts. DATA SOURCES: This review draws on literature from PubMed and Web of Science, published up to 2025, combined with evidence from the guide itself, as well as relevant consensus statements and expert recommendations. RESULTS: The guideline provides three strong recommendations, including behavioral intervention, early sleep hygiene education, and bedtime massage; four conditional recommendations under professional supervision, including separate sleeping arrangements, white noise, melatonin and iron supplementation; and three non-recommended interventions, including pacifier use, early complementary feeding, and daytime physical activity. Challenges in assessment and treatment involve the absence of standardized diagnostic criteria, reliance on subjective reports, multifactorial etiology with frequent comorbidities, and culturally embedded family sleep practices. Comprehensive evaluation requires integrating both subjective and objective measures while accounting for medical, behavioral, and environmental factors within cultural frameworks. Intervention should be individualized through shared decision-making with parents, combining modalities based on etiological profiling, with non-pharmacological strategies constituting first-line management. CONCLUSIONS: Effective management for bedtime problems and night wakings in young children requires standardized tools, and culturally adaptable, and family-centered interventions according to evidence-based guidelines. Strengthening professional training and parental education is crucial for guideline implementation and improved pediatric sleep health.
55Efficacy of Sleep Tool Education During Hospitalization: A Randomized Controlled Trial.PubMed
Peter M Farrehi, Kristen R Clore, J Ryan Scott, et al.
Am J Med. 2016 Dec;129(12):1329.e9-1329.e17. doi: 10.1016/j.amjmed.2016.08.001. Epub 2016 Aug 23.
BACKGROUND: Patients are commonly provided tools in the hospital to overcome poor sleep. Whether education on use of sleep tools can impact health outcomes from a patient perspective is not known. METHODS: We recruited 120 adults admitted to a nonintensive care unit cardiac-monitored floor. All patients received a set of sleep-enhancing tools (eye mask, ear plugs, and a white noise machine) and were randomized to receive direct education on use of and benefit of these sleep-enhancing tools (intervention), or an equal amount of time was spent discussing general benefits of sleep (control). Measurement of several symptom domains was assessed daily by health outcome survey responses, and change from baseline was assessed for differences between groups. Inpatient opioid use and length of stay were also measured. RESULTS: Participants randomized to receive the education intervention had a significantly greater decrease in fatigue scores over the 3 days, compared with controls (5.30 ± 6.93 vs 1.81 ± 6.96, t = 2.32, P = .028). There was a trend toward improvements in multiple other sleep-related domains, including sleep disturbance, sleep-related impairment, physical functioning, pain severity, or pain interference (all P >.140). There was no difference in length of stay between intervention and control groups (7.40 ± 7.29 vs 7.71 ± 6.06 days, P = .996). The change in number of opioid equivalents taken did not differ use between the groups (P = .688). CONCLUSION: In a randomized trial of education in the use of sleep-enhancing tools while hospitalized, patient fatigue was significantly improved, whereas several other patient-reported outcomes showed a trend toward improvements. Implementation of this very low-cost approach to improving sleep and well-being could substantially improve the patient care experience.
56Nighttime ambient temperature and sleep in community-dwelling older adults.PubMed
Amir Baniassadi, Brad Manor, Wanting Yu, et al.
Sci Total Environ. 2023 Nov 15;899:165623. doi: 10.1016/j.scitotenv.2023.165623. Epub 2023 Jul 19.
This longitudinal study examines the association between bedroom nighttime temperature and sleep quality in a sample of community dwelling older adults. Using wearable sleep monitors and environmental sensors, we assessed sleep duration, efficiency, and restlessness over an extended period within participants' homes while controlling for potential confounders and covariates. Our findings demonstrated that sleep was most efficient and restful when nighttime ambient temperature ranged between 20 and 25 °C, with a clinically relevant 5-10 % drop in sleep efficiency when the temperature increased from 25 °C to 30 °C. The associations were primarily nonlinear, and substantial between-subject variations were observed. These results highlight the potential to enhance sleep quality in older adults by optimizing home thermal environments and emphasize the importance of personalized temperature adjustments based on individual needs and circumstances. Additionally, our study underscores the potential impact of climate change on sleep quality in older adults, particularly those with lower socioeconomic status, and supports increasing their adaptive capacity in the face of a changing climate.
57Perception of feeling cold in the bedroom and sleep quality.PubMed
Odgerel Chimed-Ochir, Shintaro Ando, Shuzo Murakami, et al.
Nagoya J Med Sci. 2021 Nov;83(4):705-714. doi: 10.18999/nagjms.83.4.705.
Sleep disorders are drawing the attention of both medical and public health concern worldwide. In Japan, research suggests that one fifth of adults do not receive appropriate sleep and 40% of adults sleep less than 6 hours a day, and sleep rates are decreasing further year by year. Many studies show that cold indoor environments negatively affect sleep comfort and quality. Whereas these studies have focused on the effects of low bedroom temperature, few studies have focused on the effect of perception of coldness. Indoor temperature is typically much lower in Japan than in other countries. Therefore, the current study aimed to identify the effect of perception of bedroom coldness on sleep quality among Japanese adults. After controlling for covariates of age, presence of current disease and pain, smoking and consumption of alcohol (Model 1), participants who sometimes, often or always felt cold in the bedroom exhibited 0.57 (95% CI=0.32-0.83, p=<.0001), 1.08 (95% CI=0.82-1.35, p<.0001) or 2.25 (95% CI=1.83-2.67, p<.0001) higher PSQI scores compared to the group which didn't feel cold in bedroom. Our findings suggest keeping the bedroom thermal environment above a minimum limit as recommended by the World Health Organization or other organization during colder, winter nights when feeling cold during sleep. Additional deficiencies in the housing infrastructure, air quality issues due to the use of a heater, and micro bed environment need to be holistically addressed. Sleep quality can be improved by certain level via providing thermally comfortable sleeping environment.
58Circadian Rhythms in Gastroenterology: The Biological Clock's Impact on Gut Health.PubMed
Faraz Bishehsari, Zoë Post, Garth R Swanson, et al.
Gastroenterology. 2025 Dec;169(7):1380-1396. doi: 10.1053/j.gastro.2025.06.017. Epub 2025 Jun 28.
Chronic gastrointestinal (GI) diseases, including functional, inflammatory, and neoplastic conditions, are increasing globally, partly due to modern lifestyles. The circadian rhythm, regulated by the central clock in the hypothalamus and synchronized with peripheral clocks in the GI organs, orchestrates GI functions in response to environmental cycles. This clock is influenced by cues such as light, sleep, and eating times. The circadian machinery prepares the host to cope with environmental conditions to adjust cellular and organ function accordingly. Modern behaviors-like night-time light exposure, travel across time zones, shift work, mistimed eating, and social jet lag-disrupt the circadian clock, affecting GI processes such as digestion, absorption, motility, intestinal barrier function, immune function, and the microbiome, promoting not only GI pathology, but also systemic inflammatory and metabolic disorders. This review summarizes the circadian rhythm's role in normal GI function, examines the consequences of circadian disruption in the GI tract, and discusses circadian-based therapeutic interventions. These interventions aim to realign the circadian clock with external cues or optimize medication timing according to biological rhythms. Understanding the role of the circadian clock in GI conditions can provide preventive and therapeutic opportunities to reduce the burden of GI diseases.
59Chrono-biology, chrono-pharmacology, and chrono-nutrition.PubMed
Yu Tahara, Shigenobu Shibata
J Pharmacol Sci. 2014;124(3):320-35. doi: 10.1254/jphs.13r06cr. Epub 2014 Feb 27.
The circadian clock system in mammals drives many physiological processes including the daily rhythms of sleep-wake behavior, hormonal secretion, and metabolism. This system responds to daily environmental changes, such as the light-dark cycle, food intake, and drug administration. In this review, we focus on the central and peripheral circadian clock systems in response to drugs, food, and nutrition. We also discuss the adaptation and anticipation mechanisms of our body with regard to clock system regulation of various kinetic and dynamic pathways, including absorption, distribution, metabolism, and excretion of drugs and nutrients. "Chrono-pharmacology" and "chrono-nutrition" are likely to become important research fields in chrono-biological studies.
60Toward Precision Medicine: Circadian Rhythm of Blood Pressure and Chronotherapy for Hypertension - 2021 NHLBI Workshop Report.PubMed
Michelle L Gumz, Daichi Shimbo, Marwah Abdalla, et al.
Hypertension. 2023 Mar;80(3):503-522. doi: 10.1161/HYPERTENSIONAHA.122.19372. Epub 2022 Nov 30.
Healthy individuals exhibit blood pressure variation over a 24-hour period with higher blood pressure during wakefulness and lower blood pressure during sleep. Loss or disruption of the blood pressure circadian rhythm has been linked to adverse health outcomes, for example, cardiovascular disease, dementia, and chronic kidney disease. However, the current diagnostic and therapeutic approaches lack sufficient attention to the circadian rhythmicity of blood pressure. Sleep patterns, hormone release, eating habits, digestion, body temperature, renal and cardiovascular function, and other important host functions as well as gut microbiota exhibit circadian rhythms, and influence circadian rhythms of blood pressure. Potential benefits of nonpharmacologic interventions such as meal timing, and pharmacologic chronotherapeutic interventions, such as the bedtime administration of antihypertensive medications, have recently been suggested in some studies. However, the mechanisms underlying circadian rhythm-mediated blood pressure regulation and the efficacy of chronotherapy in hypertension remain unclear. This review summarizes the results of the National Heart, Lung, and Blood Institute workshop convened on October 27 to 29, 2021 to assess knowledge gaps and research opportunities in the study of circadian rhythm of blood pressure and chronotherapy for hypertension.
61Impact of a Low-Carbohydrate Compared with Low-Fat Breakfast on Blood Glucose Control in Type 2 Diabetes: A Randomized Trial.PubMed
Barbara F Oliveira, Courtney R Chang, Kate Oetsch, et al.
Am J Clin Nutr. 2023 Jul;118(1):209-217. doi: 10.1016/j.ajcnut.2023.04.032. Epub 2023 May 29.
BACKGROUND: In type 2 diabetes (T2D), consuming carbohydrates results in a rapid and large increase in blood glucose, particularly in the morning when glucose intolerance is highest. OBJECTIVES: We investigated if a low-carbohydrate (LC) breakfast (∼465 kcal: 25 g protein, 8 g carbohydrates, and 37 g fat) could improve glucose control in people with T2D when compared with a low-fat control (CTL) breakfast (∼450 kcal:20 g protein, 56 g carbohydrates, and 15 g fat). METHODS: Participants with T2D (N = 121, 53% women, mean age 64 y) completed a remote 3-month parallel-group randomized controlled trial comparing a LC with standard low-fat guideline CTL breakfast. The change in HbA1c was the prespecified primary outcome. Continuous glucose monitoring, self-reported anthropometrics, and dietary information were collected for an intention-to-treat analysis. RESULTS: HbA1c was reduced (-0.3%; 95% CI: -0.4%, -0.1%) after 12 wks of a LC breakfast, but the between-group difference in HbA1c was of borderline statistical significance (-0.2; 95% CI: -0.4, 0.0; P = 0.06). Self-reported total daily energy (-242 kcal; 95% CI: -460, -24 kcal; P = 0.03) and carbohydrate (-73 g; 95% CI: -101, -44 g; P < 0.01) intake were lower in the LC group but the significance of this difference is unclear. Mean and maximum glucose, area under the curve, glycemic variability, standard deviation, and time above range were all significantly lower, and time in the range was significantly higher, in the LC group compared with CTL (all P < 0.05). CONCLUSIONS: Advice and guidance to consume a LC breakfast appears to be a simple dietary strategy to reduce overall energy and carbohydrate intake and improve several continuous glucose monitoring variables when compared with a CTL breakfast in persons living with T2D. The trial was registered at clinicaltrials.gov as NCT04550468.
62'Post-lunch' sleepiness during prolonged, monotonous driving - effects of meal size.PubMed
L A Reyner, S J Wells, V Mortlock, et al.
Physiol Behav. 2012 Feb 28;105(4):1088-91. doi: 10.1016/j.physbeh.2011.11.025. Epub 2011 Dec 6.
The 'post-lunch' dip is a bi-circadian phenomenon, largely unrelated to lunch, and worsened by a disturbed prior night's sleep. Despite anecdotal claims of adverse effects of larger lunches on afternoon driving ability, there is little actual driving data to support this belief. Although there have been various (non-driving) laboratory studies assessing meal size and micronutrient effects on psychological performance tests, findings are mixed. Moreover, most have not utilised heightened afternoon sleepiness after a shortened night's sleep, and few tested beyond 20 min. Using a real car interactive simulator having full size screen projection, we compared the effects on a 2h monotonous afternoon drive, of two very similar, palatable lunches ('light': 305 cal vs 'heavy': 922 cal [having 3× fat and 2× carbohydrate contents]), given double blind in a repeated measures counterbalanced design, to 12 young male drivers whose prior night's sleep had been restricted to 5h. Sleepiness-related lane drifting ('incidents'), subjective sleepiness and EEG (4-11 Hz power - indicative of sleepiness) were logged throughout. The heavy lunch caused significant increases to both incidents and EEG power, and a trend for greater subjective sleepiness. All three indices showed a significant worsening of sleepiness over the drive under both lunch conditions. Whilst there were no significant condition×time interactions, there was no difference between lunches for at least the first 30 min of the drive when, thereafter, the differences appeared. Ours was a realistic driving study, utilising typical lunches, following an unexceptional level of prior sleep loss, and where a heavy lunch exacerbated inherent sleepiness, to further impair monotonous driving.
63Effects of protein and carbohydrate meals on mood and performance: interactions with sex and age.PubMed
B Spring, O Maller, J Wurtman, et al.
J Psychiatr Res. 1982;17(2):155-67. doi: 10.1016/0022-3956(82)90017-6.
Normal adult subjects (n = 184) consumed a high-protein or high-carbohydrate meal. Two hours later their mood and performance were tested. The effects of meal composition on mood were different for men and women, and for older and younger subjects. Females, but not males, reported greater sleepiness after a carbohydrate as opposed to a protein meal. Male subjects, but not females, reported greater calmness after a carbohydrate as opposed to a protein meal. Older subjects responded differently to meals depending upon the time of day when these were consumed. When meals were eaten for breakfast (but not for lunch) individuals 40 yr of age or older felt more tense and less calm after a protein than after a carbohydrate meal. Although older subjects reported subjective discomfort after a morning protein meal, they displayed objective performance impairments after a carbohydrate lunch. Subjects 40 yr of age or older were impaired on a test of sustained selective attention (dichotic shadowing) after consuming a high-carbohydrate lunch. The shadowing impairment after carbohydrate consumption was as pronounced without distraction as with distraction and resulted mostly from increased omission errors. Our findings suggest negative effects on concentration when older subjects consume a high-carbohydrate, low-protein lunch. These negative effects of carbohydrate consumption appear to arise predominantly from lapses of attention rather than from intrusion of distractors.
64[Nutrition in improving sleep quality and fighting insomnia].PubMed
Rosa M Ortega, Ana Isabel Jiménez-Ortega, África Peral-Suárez, et al.
Nutr Hosp. 2025 Sep 11;42(Spec No1):43-46. doi: 10.20960/nh.06090.
Sleep is essential for a wide range of physiological and mental functions, but it is increasingly disturbed, which is associated with short- and long-term health damage. There are many factors involved in the deterioration of sleep quality, but from a nutritional point of view, an intake of tryptophan is useful in increasing serotonin and melatonin, but because of their competition with long-chain neutral amino acids to cross the blood-brain barrier, some proteins such as milk and eggs with high tryptophan/long-chain neutral amino acids are more useful. The adequate supply of carbohydrates and omega-3 fatty acids is favorable, while excess fat and saturated fat are harmful. In relation to vitamins, it has been shown that an adequate supply of pyridoxine, vitamin B12, folates, niacin, vitamin D and antioxidants (vitamin C, beta-carotene) help prevent sleep disturbance. In the case of minerals, various studies point to the importance of adequate iron, magnesium and zinc situation. Among the foods that are associated with benefits in sleep quality, milk and dairy products, fruits, vegetables and blue fish can be highlighted, while alcohol, energy drinks and caffeine are sleep-disrupting. Improving diet and lifestyle is a step in the fight against insomnia and improved sleep quality.
65A Comprehensive Review of Nutritional Influences on the Serotonergic System.PubMed
Justin Tang, Luke Krushelnycky, Abir Shaqo, et al.
Adv Nutr. 2025 Nov;16(11):100524. doi: 10.1016/j.advnut.2025.100524. Epub 2025 Sep 23.
Serotonin (5-hydroxytryptamine) is a critical monoamine neurotransmitter and hormone that orchestrates a vast array of physiological and psychological processes, including mood, sleep, appetite, and gastrointestinal motility. Serotonin synthesis is dependent on the availability of its dietary precursor, the essential amino acid tryptophan, and it affects biochemical pathways that may be modulated by other nutrients. We conducted a literature search to comprehensively examine the nutritional influences on the serotonergic system. Relevant original research, systematic reviews, meta-analyses, and clinical trial reports were retrieved from PubMed, Scopus, and Google Scholar, with additional articles identified from reference lists of published review papers. Key nutritional determinants of serotonergic function include macronutrients that influence the tryptophan-to-large neutral amino acid ratio (a regulator of tryptophan availability in the brain) and micronutrients, such as B-vitamins, vitamin D, iron, and magnesium, that serve as essential cofactors in serotonin synthesis and metabolism. Emerging evidence also highlights the role of the gut microbiota, shaped by dietary components, prebiotics, and probiotics, in modulating serotonergic function across both central and peripheral systems. Nutritional factors that affect serotonin have been increasingly linked to conditions such as depression, anxiety, sleep disturbances, disordered eating, obesity, and irritable bowel syndrome. Altogether, this review emphasizes the profound impact of nutrition on serotonergic regulation and advocates for targeted dietary approaches as promising catalysts for optimizing human health. Key research gaps and future directions are outlined to help advance the translation of current evidence into precise nutritional guidelines and clinical applications, with the complexity of serotonin pathways as an important consideration.
66Exploring the Role of Dairy Products In Sleep Quality: From Population Studies to Mechanistic Evaluations.PubMed
Marie-Pierre St-Onge, Faris M Zuraikat, Mackenzie Neilson
Adv Nutr. 2023 Mar;14(2):283-294. doi: 10.1016/j.advnut.2023.01.004. Epub 2023 Jan 31.
Poor sleep quality and insufficient sleep affect a large portion of the population. This is concerning given increasing evidence that poor sleep health is a behavioral risk factor for the development of cardiometabolic diseases. A healthy diet is associated with a plethora of favorable health outcomes, and emerging research now highlights diet as a potential determinant of sleep health that could be leveraged to improve sleep quality. Dairy products are notably rich in tryptophan (Trp), a key substrate for serotonin and melatonin production, which are instrumental for initiating and maintaining sleep. Furthermore, dairy products provide a range of micronutrients that serve as cofactors in the synthesis of melatonin from Trp, which could contribute to sleep-promoting effects. In this review, we evaluate population studies and clinical trials to examine a possible link between dairy consumption and sleep. Available epidemiologic studies illustrate positive associations between dairy intake and sleep outcomes. Moreover, some intervention studies support a causal effect of dairy intake on sleep. Given these data, we discuss potential mechanisms, invite additional clinical research on this topic, and provide insights on how limitations of current studies can be addressed in future trials.
67Nutritional Interventions for Enhancing Sleep Quality: The Role of Diet and Key Nutrients in Regulating Sleep Patterns and Disorders.PubMed
Rony Abou-Khalil
Food Sci Nutr. 2025 Dec 4;13(12):e71309. doi: 10.1002/fsn3.71309. eCollection 2025 Dec.
Sleep disorders and poor sleep quality are increasingly recognized as global health concerns, with substantial consequences for mental and physical health. While pharmacological treatments are available, growing evidence suggests that nutritional interventions offer effective, sustainable alternatives for enhancing sleep quality. This review aims to synthesize current evidence on the impact of key nutrients, dietary patterns, bioactive compounds, and gut microbiome modulation on sleep regulation, and to explore emerging personalized nutrition approaches for managing sleep disorders. A comprehensive review of clinical trials, observational studies, and mechanistic research published over the past two decades was conducted. Key focus areas included sleep-supportive nutrients, dietary patterns (e.g., Mediterranean, ketogenic, plant-based diets), chrononutrition, gut-brain axis modulation, functional foods, and personalized nutrition strategies. Evidence supports the role of specific nutrients (e.g., magnesium, tryptophan, omega-3 fatty acids) and dietary patterns rich in anti-inflammatory and antioxidant compounds in improving sleep outcomes. Functional foods such as tart cherry juice and kiwifruit demonstrate potential benefits. The gut microbiome emerges as a significant regulator of sleep physiology, suggesting probiotics and prebiotics as novel interventions. Personalized nutrition approaches, incorporating genetic, metabolic, and lifestyle factors, offer promising individualized solutions. Nutritional interventions represent a promising, non-pharmacological strategy for improving sleep quality and managing sleep disorders. Future research should focus on personalized approaches and large-scale clinical trials to validate and refine these strategies for clinical practice.
68Psychological and Sleep Effects of Tryptophan and Magnesium-Enriched Mediterranean Diet in Women with Fibromyalgia.PubMed
Alejandro Martínez-Rodríguez, Jacobo Á Rubio-Arias, Domingo J Ramos-Campo, et al.
Int J Environ Res Public Health. 2020 Mar 26;17(7):2227. doi: 10.3390/ijerph17072227.
Anxiety, mood disturbance, eating and sleep disorders, and dissatisfaction with body image are prevalent disorders in women with fibromyalgia. The authors of this study aimed to determine the effects of tryptophan (TRY) and magnesium-enriched (MG) Mediterranean diet on psychological variables (trait anxiety, mood state, eating disorders, self-image perception) and sleep quality in women with fibromyalgia ( = 22; 49 ± 5 years old). In this randomized, controlled trial, the participants were randomly assigned to the experimental group and the placebo group. The intervention group received a Mediterranean diet enriched with high doses of TRY and MG (60 mg of TRY and 60 mg of MG), whereas the control group received the standard Mediterranean diet. Pittsburgh Sleep Quality Questionnaire, Body Shape Questionnaire, State-Trait Anxiety Inventory (STAI), Profile of Mood States (POMS-29) Questionnaire, Eating Attitudes Test-26, and Trait Anxiety Inventory were completed before and 16 weeks after the intervention. Significant differences were observed between groups after the intervention for the mean scores of trait anxiety ( = 0.001), self-image perception ( = 0.029), mood disturbance ( = 0.001), and eating disorders ( = 0.006). This study concludes that tryptophan and magnesium-enriched Mediterranean diet reduced anxiety symptoms, mood disturbance, eating disorders, and dissatisfaction with body image but did not improve sleep quality in women with fibromyalgia.
69From Garden to Pillow: Understanding the Relationship between Plant-Based Nutrition and Quality of Sleep.PubMed
Neslihan Arslan, Eda Bozkır, Tevfik Koçak, et al.
Nutrients. 2024 Aug 13;16(16):2683. doi: 10.3390/nu16162683.
The effect of diet on sleep quality has been addressed in many studies; however, whether/how plant-based diets (PBDs) impact sleep-related parameters has not been explored in detail. This review aims to give an overview of the components of PBDs and the possible mechanisms through which PBDs may improve sleep quality. Studies have indicated that diets such as PBDs, which are typically high in fruits, vegetables, nuts, seeds, whole grains, and fiber, are associated with better sleep outcomes, including less fragmented sleep and improved sleep duration. Several mechanisms may explain how PBDs impact and/or improve sleep outcomes. Firstly, PBDs are characteristically rich in certain nutrients, such as magnesium and vitamin B6, which have been associated with improved sleep patterns. Secondly, PBDs are often lower in saturated fats and higher in fiber, which may contribute to better overall health, including sleep quality. Additionally, plant bioactive compounds like phytochemicals and antioxidants in fruits, vegetables, and herbs may have sleep-promoting effects. According to available data, PBD and Mediterranean diet elements promise to enhance sleep quality; however, it is crucial to note that diets should be customized based on each person's needs.
70Biological Rhythm Disruption Associated with Obesity in School Children.PubMed
Leticia Reis Pereira, Fernanda Pedrotti Moreira, Amanda Neumann Reyes, et al.
Child Obes. 2019 Apr;15(3):200-205. doi: 10.1089/chi.2018.0212. Epub 2019 Jan 29.
BACKGROUND: Biological rhythm is the daily metabolic cycle of mammals that involves the sleep-wake cycles, hormone release, eating habits and digestion, body temperature, and other important bodily functions that are repeated daily. Thus, greater difficulty in maintaining the circadian rhythms may be involved in the increased risk of obesity. This study assessed the association between biological rhythm disruption and childhood obesity among school children. METHODS: This is a cross-sectional study with 7-8-year-old school children enrolled in a public school in the city of Pelotas-RS. The sample was drawn through multistage sampling. The Biological Rhythms Interview of Assessment in Neuropsychiatry-Kids (BRIAN-Kids) was used to assess the degree of difficulty maintaining the biological rhythm. BMI was calculated as weight/height (kg/m). RESULTS: A total of 596 children and their caregivers participated in this study. The prevalence of obesity was 24% among school children, 28.9% for girls, and 19.4 for boys (p = 0.009). Obese children had greater difficulties in maintaining the biological rhythm compared to nonobese children (p = 0.007). Some of these difficulties included sleep (p = 0.008), overall activities (p = 0.027), social rhythm (p = 0.033), and eating (p = 0.032) pattern. CONCLUSION: Approximately one-quarter of children were obese. This finding was associated with the caregiver characteristics and some difficulties in maintaining the biological rhythm.
71The effects of physical activity on sleep: a meta-analytic review.PubMed
M Alexandra Kredlow, Michelle C Capozzoli, Bridget A Hearon, et al.
J Behav Med. 2015 Jun;38(3):427-49. doi: 10.1007/s10865-015-9617-6. Epub 2015 Jan 18.
A significant body of research has investigated the effects of physical activity on sleep, yet this research has not been systematically aggregated in over a decade. As a result, the magnitude and moderators of these effects are unclear. This meta-analytical review examines the effects of acute and regular exercise on sleep, incorporating a range of outcome and moderator variables. PubMed and PsycINFO were used to identify 66 studies for inclusion in the analysis that were published through May 2013. Analyses reveal that acute exercise has small beneficial effects on total sleep time, sleep onset latency, sleep efficiency, stage 1 sleep, and slow wave sleep, a moderate beneficial effect on wake time after sleep onset, and a small effect on rapid eye movement sleep. Regular exercise has small beneficial effects on total sleep time and sleep efficiency, small-to-medium beneficial effects on sleep onset latency, and moderate beneficial effects on sleep quality. Effects were moderated by sex, age, baseline physical activity level of participants, as well as exercise type, time of day, duration, and adherence. Significant moderation was not found for exercise intensity, aerobic/anaerobic classification, or publication date. Results were discussed with regards to future avenues of research and clinical application to the treatment of insomnia.
72Review of Under-Recognized Adjunctive Therapies for Cancer.PubMed
Mary E Money, Carolyn M Matthews, Jocelyn Tan-Shalaby
Cancers (Basel). 2022 Sep 29;14(19):4780. doi: 10.3390/cancers14194780.
Patients and providers may not be aware that several adjunctive measures can significantly improve the quality of life, response to treatment, and possibly outcomes for cancer patients. This manuscript presents a review of practical under-recognized adjunctive therapies that are effective including exercise; stress-reduction techniques such as mindfulness, massage, yoga, Tai Chi, breathing exercises; importance of sleep quality; diet modifications such as calorie restriction at the time of chemotherapy and avoidance of high carbohydrate foods; supplements such as aspirin, green tea, turmeric, and melatonin; and repurposed prescription medications such as metformin and statins. Each recommendation should be tailored to the individual patient to assure no contraindications.
73Morning or evening activity improves neuropsychological performance and subjective sleep quality in older adults.PubMed
Susan Benloucif, Larry Orbeta, Rosemary Ortiz, et al.
Sleep. 2004 Dec 15;27(8):1542-51. doi: 10.1093/sleep/27.8.1542.
STUDY OBJECTIVES: Sleep disturbances and decline in neuropsychological performance are common in older adults. Reduced social and physical activity is likely a contributing factor for these age-related changes in sleep and cognition. We previously demonstrated that a program of structured social and physical activity, with 2 daily activity sessions, 1 in the morning and 1 in the evening for a relatively short period of 2 weeks, improved sleep and neuropsychological performance in community-dwelling older adults. The goals of this pilot study were to determine whether a single daily morning or evening activity session for 2 weeks would also improve sleep and neuropsychological function and whether these effects were dependent on the timing of the activity sessions. DESIGN: We compared the effect of morning or evening structured activity sessions in a repeated-measures crossover design. Subjective mood, neuropsychological performance tasks, and subjective and objective measures of sleep were assessed at baseline and after the intervention. SETTING: All procedures took place in the participant's residence. PARTICIPANTS: Twelve older men and women (74.6 +/- 5.5 years of age). INTERVENTIONS: Subjects participated in 14 days of structured activity sessions in the morning (9:00-10:30 am) or evening (7:00-8:30 pm). Sessions consisted of stretching, low-impact aerobics, and game playing. MEASUREMENTS AND RESULTS: Exposure to either morning or evening activity significantly improved performance on a neuropsychological test battery. Morning activity sessions increased throughput on 4 of 8 performance tasks, while evening activity sessions improved throughput on 7 of the 8 performance tasks. Subjective sleep-quality ratings, measured by the Pittsburg Sleep Quality Index, improved following activity sessions in either the morning or the evening. Objective measures of sleep did not improve when measured by actigraphy or polysomnography. CONCLUSIONS: These results suggest that short-term exposure to either morning or evening social and physical activity improves objective measures of neuropsychological performance and subjective sleep quality in the elderly. Increasing exposure to social and physical activity may be a useful intervention to improve sleep quality and daytime function in older adults.
74The effect of resistance exercise on sleep: A systematic review of randomized controlled trials.PubMed
Ana Kovacevic, Yorgi Mavros, Jennifer J Heisz, et al.
Sleep Med Rev. 2018 Jun;39:52-68. doi: 10.1016/j.smrv.2017.07.002. Epub 2017 Jul 19.
Impaired sleep quality and quantity are associated with future morbidity and mortality. Exercise may be an effective non-pharmacological intervention to improve sleep, however, little is known on the effect of resistance exercise. Thus, we performed a systematic review of the literature to determine the acute and chronic effects of resistance exercise on sleep quantity and quality. Thirteen studies were included. Chronic resistance exercise improves all aspects of sleep, with the greatest benefit for sleep quality. These benefits of isolated resistance exercise are attenuated when resistance exercise is combined with aerobic exercise and compared to aerobic exercise alone. However, the acute effects of resistance exercise on sleep remain poorly studied and inconsistent. In addition to the sleep benefits, resistance exercise training improves anxiety and depression. These results suggest that resistance exercise may be an effective intervention to improve sleep quality. Further research is needed to better understand the effects of acute resistance exercise on sleep, the physiological mechanisms underlying changes in sleep, the changes in sleep architecture with chronic resistance exercise, as well its efficacy in clinical cohorts who commonly experience sleep disturbance. Future studies should also examine time-of-day and dose-response effects to determine the optimal exercise prescription for sleep benefits.
75The effect of 24-hour sleep deprivation and anaerobic exercise on the expression of BAX, BCL2, BMAL1 and CCAR2 genes in peripheral blood mononuclear cells after L-arginine supplementation.PubMed
Mirzahossein Norouzi Kamareh, Mohammad Samadi, Ehsan Arabzadeh, et al.
Gene. 2023 Dec 15;887:147732. doi: 10.1016/j.gene.2023.147732. Epub 2023 Aug 23.
Sleep deprivation disrupt the circadian clock and exercise performance. Defective oxidative stress caused by sleep deprivation may affect the expression of genes involved in cell apoptosis. Since a number of studies have shown the anti-apoptotic effect of L-arginine, so the aim of this study was to evaluate the effect of eight weeks of L-arginine supplementation on the expression of brain and muscle ARNT-like protein 1 (BMAL1), cell cycle and apoptosis regulator 2 (CCAR2), and BAX and BCL2 genes during sleep deprivation and acute anaerobic exercise. Participants included 20 healthy men age 26-35 years, randomized into the L-arginine intervention group (n = 10) and a placebo control (n = 10). The running-based anaerobic sprint test (RAST) was used for anaerobic exercise. Intervention subjects took one 1000 mg L-arginine tablet daily for 8 weeks. The Real-Time PCR method was used to determine apoptosis gene expression in peripheral blood mononuclear cells (PBMCs). Acute anaerobic exercise and sleep deprivation both increased the expression of BAX and CCAR2 genes, and decreased the expression of BCL2 and BMAL1 genes (p < 0.05 for all). L-arginine supplementation increased the expression of BMAL1 and BCL2 genes and decreased the expression of BAX and CCAR2 genes relative to control (p < 0.05). L-Arginine controlled the increase in expression of BAX and CCAR2 genes and the decrease in expression of BCL2 and BMAL1 genes in response to sleep deprivation and acute anaerobic exercise (p < 0.05). Our results showed that 24-hour sleep deprivation and acute anaerobic exercise increased the expression of pro-apoptotic genes (BAX and CCAR2) and decreased the expression of anti-apoptotic genes (BCL2 and BMAL1), although the effect of sleep deprivation is greater. In this situation, L-arginine supplementation may balance the apoptotic state of peripheral blood mononuclear cells. However, any recommendation about this needs further research.
76Effect of caffeine supplementation on anaerobic and aerobic performance in sleep-restricted male college soccer players.PubMed
Ruiqi Cheng, Ning Wang, Weili He, et al.
Front Physiol. 2025 Mar 19;16:1561695. doi: 10.3389/fphys.2025.1561695. eCollection 2025.
UNLABELLED: This study aimed to explore the effects of sleep restriction of ≤5 h within 24 h on anaerobic and aerobic performance in male college soccer players and evaluated the effects of acute supplementation of 3 mg⋅kg caffeine on the aerobic and anaerobic performance of college male soccer players under sleep restriction. METHODS: 10 college male soccer players were recruited, and a randomized crossover experimental design was adopted. The subjects received three intervention treatments in a randomized crossover order: Normal sleep night (NSN), sleep restriction night supplemented with placebo (SRP), and sleep restriction night supplemented with 3 mg⋅kg caffeine (SRC), and participated in the Running-Based Anaerobic Sprint Test (RAST) and 30-15 Intermittent Fitness Test (30-15). RESULTS: The main effect of the RAST and the 30-15 scores was significant (P<0.05). Post hoc analyses showed that the peak power, mean power, peak power/body mess, mean power/body mess, peak velocity mean velocity, fatigue index of the RAST, and the velocity of the intermittent fitness test (V), maximal oxygen uptake (VO), and time to exhaustion (TTE) of the 30-15 in the SRP group were significantly lower than those of the NSN group (P < 0.05), and the total time of the RAST was significantly higher than that of the NSN group (P < 0.05); there were significant differences between the V, VO and TTE indicators tested at 30-15 between the SRC group and the SRP group (P < 0.05). Still, other indicators had no significant differences (P > 0.05). CONCLUSION: Sleep restriction harms the anaerobic repeated sprint and aerobic performance of college soccer players; acute supplementation of 3 mg⋅kg of caffeine can effectively reduce the negative impact of insufficient sleep the night before on the aerobic endurance performance of college soccer players. Athletes or coaches should consider caffeine supplementation as a strategy to alleviate the negative impacts of sleep deprivation, but individual tolerance and potential side effects should be taken into account.
77Effectiveness of Aerobic Exercise and Tai Chi Interventions on Sleep Quality in Patients With Advanced Lung Cancer: A Randomized Clinical Trial.PubMed
Naomi Takemura, Denise Shuk Ting Cheung, Daniel Yee Tak Fong, et al.
JAMA Oncol. 2024 Feb 1;10(2):176-184. doi: 10.1001/jamaoncol.2023.5248.
IMPORTANCE: Sleep disturbances prevalent among patients with advanced lung cancer can aggravate physical and psychological symptoms, contributing to decreased quality of life and survival. OBJECTIVE: To compare the effectiveness of 2 physical activities of different modalities and intensities, namely aerobic exercise (AE) and tai chi (TC), on subjective sleep quality, physical and psychological outcomes, and survival in patients with advanced lung cancer. DESIGN, SETTING, AND PARTICIPANTS: This assessor-blinded, randomized clinical trial was conducted in 3 public hospitals in Hong Kong between December 19, 2018, and September 7, 2022. A total of 226 patients with advanced lung cancer were recruited and randomized 1:1:1 to AE, TC, or the control group. INTERVENTIONS: For 16 weeks, the AE group received two 60-minute supervised group exercise sessions and home-based exercises per month, and the TC group received 60-minute group sessions twice weekly. The control group received physical activity guidelines. MAIN OUTCOMES AND MEASURES: The primary outcome was subjective sleep quality. Secondary outcomes included objective sleep measures, anxiety, depression, fatigue, quality of life, physical function, circadian rhythm, and 1-year survival. Assessments were conducted at baseline, 16 weeks (T1), and 1 year (T2). RESULTS: The 226 participants had a mean (SD) age of 61.41 (8.73) years, and 122 (54.0%) were female. Compared with the control group, participants in the AE and TC groups showed statistically significant improvements in subjective sleep quality from baseline to T1 (AE: between-group difference, -2.72; 95% CI, -3.97 to -1.46; P < .001; TC: between-group difference, -4.21; 95% CI, -5.48 to -2.94; P < .001) and T2 (AE: between-group difference, -1.75; 95% CI, -3.24 to -0.26; P = .02; TC: between-group difference, -3.95; 95% CI, -5.41 to -2.49; P < .001), psychological distress, physical function, step count, and circadian rhythm. The TC group had a statistically significant greater improvement in sleep than the AE group at T1 (between-group difference, -1.49; 95% CI, -2.77 to -0.22; P = .02) and T2 (between-group difference, -2.20; 95% CI, -3.57 to -0.83; P < .001). Participants in the TC group showed statistically significant improvement in survival compared with the control group. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, AE and TC improved sleep, psychological distress, physical function, and circadian rhythm, with TC demonstrating greater benefits on sleep and survival. Both exercises, but particularly TC, can be incorporated into lung cancer survivorship care. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04119778.
78Comparative efficacy of exercise regimens on sleep quality in older adults: A systematic review and network meta-analysis.PubMed
Faizul Hasan, Yu-Kang Tu, Chih-Ming Lin, et al.
Sleep Med Rev. 2022 Oct;65:101673. doi: 10.1016/j.smrv.2022.101673. Epub 2022 Aug 27.
The efficacies of various exercise modalities in improving older adults' sleep quality remain unclear. Therefore, in this study, network meta-analysis was performed by comparing the efficacies of various exercise regimens in improving sleep quality in this age group. Six electronic databases were searched for relevant studies between the date of database creation and August 13, 2021. Only randomized controlled trials reporting the effects of exercise on sleep quality in this population were included. Random-effects network meta-analysis based on a frequentist framework was conducted. In total, 35 trials involving 3519 older adults were included. Cognitive behavioral therapy for insomnia, muscle endurance training combined with walking, Tai chi, Baduanjin, resistance training combined with walking, and resistance training significantly improved sleep quality to a greater degree than did usual care (P < 0.05). Muscle endurance training combined with walking led to significantly higher sleep quality than did regimens involving sleep hygiene, Pilates, only walking, health education, resistance training, Taichi, resistance training combined with walking, or yoga. Muscle endurance training combined with walking was identified as the optimal exercise program (88.9%) for enhancing sleep quality in older adults. The results of this study support the claim that exercise can improve sleep quality in this population. PROSPERO registration number: CRD42020178209.
79Effects of mind-body exercise on perimenopausal and postmenopausal women: a systematic review and meta-analysis.PubMed
Hong Xu, Jian Liu, Peishan Li, et al.
Menopause. 2024 May 1;31(5):457-467. doi: 10.1097/GME.0000000000002336.
IMPORTANCE: The increasing attention to the management of perimenopausal and postmenopausal women parallels the growth of the aging population. Although hormone therapy is commonly used to alleviate menopausal symptoms, it carries a potential risk of cancer. Recently, mind-body exercises have emerged as innovative approaches for improving menopausal symptoms and bone health. However, research findings have needed to be more consistent, highlighting the significance of this study's systematic review of mind-body exercise effects on perimenopausal and postmenopausal women. OBJECTIVE: This study aims to evaluate the impact of mind-body exercises, including tai chi, yoga, Pilates, qigong, baduanjin, and mindfulness-based stress reduction, on bone mineral density, sleep quality, anxiety, depression, and fatigue among perimenopausal and postmenopausal women. EVIDENCE REVIEW: Four electronic databases-PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science-were systematically searched from inception until July 2023. The search focused exclusively on randomized controlled trials to examine the impact of mind-body exercise interventions on perimenopausal and postmenopausal women. The methodological quality of the included studies was evaluated using the Cochrane Bias Risk Assessment tool. FINDINGS: A total of 11 randomized controlled trials, comprising 1,005 participants, were included in the analysis. Traditional meta-analysis indicated that mind-body exercise significantly enhanced bone mineral density in perimenopausal and postmenopausal women compared with control groups, with a standardized mean difference (SMD) of 0.41 (95% CI, 0.17 to 0.66; P = 0.001, I2 = 7%). In addition, significant improvements were observed in sleep quality (SMD, -0.48; 95% CI, -0.78 to -0.17; P = 0.002, I2 = 76%), anxiety reduction (SMD, -0.80; 95% CI, -1.23 to -0.38; P = 0.0002, I2 = 84%), depressive mood (SMD, -0.80; 95% CI, -1.17 to -0.44; P < 0.0001, I2 = 79%), and fatigue (SMD, -0.67; 95% CI, -0.97 to -0.37; P < 0.0001, I2 = 0%). CONCLUSIONS AND RELEVANCE: The findings of this meta-analysis demonstrate that mind-body exercise positively influences bone mineral density, sleep quality, anxiety, depression, and fatigue among perimenopausal and postmenopausal women.
80Complementary and alternative medicine for sleep disturbances in older adults.PubMed
Nalaka S Gooneratne
Clin Geriatr Med. 2008 Feb;24(1):121-38, viii. doi: 10.1016/j.cger.2007.08.002.
Complementary and alternative medicines (CAM) are frequently used for the treatment of sleep disorders, but in many cases patients do not discuss these therapies directly with their health care provider. There is a growing body of well-designed clinical trials using CAM that have shown the following: (1) Melatonin is an effective agent for the treatment of circadian phase disorders that affect sleep; however, the role of melatonin in the treatment of primary or secondary insomnia is less well established. (2) Valerian has shown a benefit in some, but not all clinical trials. (3) Several other modalities, such as Tai Chi, acupuncture, acupressure, yoga, and meditation have improved sleep parameters in a limited number of early trials. Future work examining CAM has the potential to significantly add to our treatment options for sleep disorders in older adults.
81Effect of exercise based interventions on sleep and circadian rhythm in cancer survivors-a systematic review and meta-analysis.PubMed
Rachita Gururaj, Stephen Rajan Samuel, K Vijaya Kumar, et al.
PeerJ. 2024 Mar 8;12:e17053. doi: 10.7717/peerj.17053. eCollection 2024.
BACKGROUND: Disrupted circadian rhythm commonly reported in cancer survivors is closely associated with cancer related fatigue, sleep disturbances and compromised quality of life. As more cancer survivors request non-pharmacological treatment strategies for the management of their chronic sleep-related symptoms, there is a need for meta-analyses of various interventions such as exercise on sleep and circadian rhythm disturbances. METHODS: A search for RCT's was conducted in April 2020 and updated in July 2023 using relevant keywords for cancer, sleep, circadian rhythm and exercise interventions on PubMed, Scopus, Web of Science, PEDro and CINAHL. RESULTS: Thirty-six studies were included for qualitative analysis and 26, for meta-analysis. Thirty-five studies analyzed sleep outcomes, while five analyzed circadian rhythm. RCT's studying the effect of aerobic exercise, resistance exercise, combined aerobic and resistance exercise, physical activity, yoga, or tai chi were included. Meta-analysis results showed significant exercise-related improvements on sleep quality assessed by Pittsburgh Sleep Quality index (PSQI) (SMD = -0.50 [-0.87, -0.13], = 0.008), wake after sleep onset (WASO) (SMD = -0.29 [-0.53, -0.05], = 0.02) and circadian rhythm, assessed by salivary cortisol levels (MD = -0.09 (95% CI [-0.13 to -0.06]) mg/dL, < 0.001). Results of the meta-analysis indicated that exercise had no significant effect on sleep efficiency, sleep onset latency, total sleep time and circadian rhythm assessed by accelerometry values. CONCLUSION: While some sleep and circadian rhythm outcomes (PSQI, WASO and salivary cortisol) exhibited significant improvements, it is still somewhat unclear what exercise prescriptions would optimize different sleep and circadian rhythm outcomes across a variety of groups of cancer survivors. IMPLICATION: As exercise does not exacerbate cancer-related circadian rhythm and sleep disturbances, and may actually produce some significant benefits, this meta-analysis provides further evidence for cancer survivors to perform regular exercise.
82Non-drug therapies for the secondary prevention of lower limb muscle cramps.PubMed
Fiona Hawke, Sean G Sadler, Hans Dieter Katzberg, et al.
Cochrane Database Syst Rev. 2021 May 17;5(5):CD008496. doi: 10.1002/14651858.CD008496.pub3.
BACKGROUND: Lower limb muscle cramps are common and painful. They can limit exercise participation, and reduce quality of sleep, and quality of life. Many interventions are available for lower limb cramps; some are controversial or could cause harm, and often, people experience no benefit from the interventions used. This is an update of a Cochrane Review first published in 2012. We updated the review to incorporate new evidence. OBJECTIVES: To assess the effects of non-drug, non-invasive therapies for lower limb muscle cramps. SEARCH METHODS: In August 2018 and May 2020, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, the World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, and reference lists of included studies. We imposed no restrictions by language or publication date. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) of non-drug, non-invasive interventions tested over at least four weeks, for lower limb muscle cramps in any group of people, except pregnant women. The primary outcome was cramp frequency. Secondary outcomes were cramp pain severity, cramp duration, health-related quality of life, quality of sleep, participation in activities of daily living, proportion of participants reporting lower limb muscle cramps, and adverse events. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, assessed risk of bias, and cross-checked data extraction and analyses according to standard Cochrane procedures. MAIN RESULTS: We included three trials, with 201 participants, all 50 years of age and older; none had neurological disease. All trials evaluated a form of stretching for lower limb muscle cramps. A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps (measured on a 10 cm visual analogue scale (VAS) where 0 = no pain and 10 cm = worst pain imaginable) in people aged 55 years and older, compared to no intervention (mean difference (MD) -1.30, 95% confidence interval (CI) -1.74 to -0.86; 1 RCT, 80 participants; low-certainty evidence). The certainty of evidence was very low for cramp frequency (change in number of cramps per night from week zero to week six) comparing the stretching group and the no intervention group (MD -1.2, 95% CI -1.8 to -0.6; 80 participants; very low-certainty evidence). Calf stretching alone for 12 weeks may make little to no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older (stretching group median number of cramps in the last four weeks (Md) 4, interquartile range (IQR) 8; N = 48; sham stretching group Md 3, IQR 7.63; N = 46) (U = 973.5, z = -0.995, P = 0.32, r = 0.10; 1 RCT, 94 participants; low-certainty evidence). This trial did not report cramp severity. The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome (N = 24). It was not possible to fully analyse the frequency data and the scale used to measure cramp severity is not validated. No study reported health-related quality of life, quality of sleep, or participation in activities of daily living. No participant in these three studies reported adverse events. The evidence for adverse events was of moderate certainty as the studies were too small to detect uncommon events. In two of the three studies, outcomes were at risk of recall bias, and tools used to measure outcomes were not validated. Due to limitations in study designs that led to risks of bias, and imprecise findings with wide CIs, we cannot be certain that findings of future studies will be similar to those presented in this review. AUTHORS' CONCLUSIONS: A combination of daily calf and hamstring stretching for six weeks may reduce the severity of night-time lower limb muscle cramps in people aged 55 years and older, but the effect on cramp frequency is uncertain. Calf stretching alone compared to sham stretching for 12 weeks may make little or no difference to the frequency of night-time lower limb muscle cramps in people aged 60 years and older. The evidence is very uncertain about the effects of a combination of daily calf, quadriceps, and hamstring stretching on the frequency and severity of leg cramps in 50- to 60-year-old women with metabolic syndrome. Overall, use of unvalidated outcome measures and inconsistent diagnostic criteria make it difficult to compare the studies and apply findings to clinical practice. Given the prevalence and impact of lower limb muscle cramps, there is a pressing need to carefully evaluate many of the commonly recommended and emerging non-drug therapies in well-designed RCTs across all types of lower limb muscle cramps. A specific cramp outcome tool should be developed and validated for use in future research.
83Efficacy of aquatic vs land-based therapy for pain management in women with fibromyalgia: a randomised controlled trial.PubMed
S Rivas Neira, A Pasqual Marques, R Fernández Cervantes, et al.
Physiotherapy. 2024 Jun;123:91-101. doi: 10.1016/j.physio.2024.02.005. Epub 2024 Feb 17.
OBJECTIVE: To determine the efficacy of two physiotherapeutic interventions - aquatic therapy (AT) and land-based therapy (LBT) - for reducing pain in women with fibromyalgia. DESIGN: Single-blind, randomised controlled, equivalence trial. SETTING: Fibromyalgia, Chronic Fatigue Syndrome and Multiple Chemical Sensitivity Association in A Coruña, Spain. PARTICIPANTS: Forty women with fibromyalgia were assigned at random in a 1:1 manner to two groups: AT (n = 20) and LBT (n = 20). INTERVENTIONS: Two therapeutic exercise programmes, with 60-min sessions, were undertaken three times per week for 12 weeks. Sessions were carried out in groups by a trained physiotherapist. OUTCOME: The primary outcome was pain intensity (visual analogue scale). The secondary outcomes were pressure pain threshold (algometer), quality of life (Revised Fibromyalgia Impact Questionnaire), sleep quality (Pittsburgh Sleep Quality Index), fatigue (Multidimensional Fatigue Inventory) and physical ability (6-Minute Walk Test). Patients were evaluated at baseline, 12 weeks (post-treatment) and 18 weeks (follow-up). The statistical analysis was per-protocol. P < 0.05 was considered to indicate significance. Effect size was calculated. RESULTS: The mean age was 50 [standard deviation (SD) 9] years, with median body mass index of 27 [interquartile range (IQR) 25-30] kg/m and median symptom duration of 11 (IQR 6-15) years. No differences were observed between the groups post-treatment, but differences in favour of AT were found in pain intensity [2.7 (IQR 1.5-4.9) vs 5.5 (IQR 3.3-7.6); p= 0.023; large effect, Cohen's d= 0.8; 95% confidence interval (CI) 0.1-1.5] and sleep quality [12.0 (IQR 7.3-15.3) vs 15.0 (IQR 13.0-17.0); p= 0.030; large effect, Cohen's d= 0.8; 95% CI 0.1-1.5] at follow-up. CONCLUSIONS: The results suggest that AT is better than LBT for reducing pain intensity and improving sleep quality after 6 weeks of follow-up. AT may be a good treatment option for women with fibromyalgia. CLINICAL TRIALS REGISTRATION NUMBER: ClinicalTrials.gov NCT02695875 CONTRIBUTION OF THE PAPER.
84A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative?PubMed
Amber Brooks, Leon Lack
Sleep. 2006 Jun;29(6):831-40. doi: 10.1093/sleep/29.6.831.
STUDY OBJECTIVES: The purposes of this study were to compare the benefits of different length naps relative to no nap and to analyze the electroencephalographic elements that may account for the benefits. DESIGN: A repeated-measures design included 5 experimental conditions: a no-nap control and naps of precisely 5, 10, 20, and 30 minutes of sleep. SETTING: Nocturnal sleep restricted to about 5 hours in participants' homes was followed by afternoon naps at 3:00 PM and 3 hours of postnap testing conducted in a controlled laboratory environment. PARTICIPANTS: Twenty-four healthy, young adults who were good sleepers and not regular nappers. MEASUREMENTS AND RESULTS: The 5-minute nap produced few benefits in comparison with the no-nap control. The 10-minute nap produced immediate improvements in all outcome measures (including sleep latency, subjective sleepiness, fatigue, vigor, and cognitive performance), with some of these benefits maintained for as long as 155 minutes. The 20-minute nap was associated with improvements emerging 35 minutes after napping and lasting up to 125 minutes after napping. The 30-minute nap produced a period of impaired alertness and performance immediately after napping, indicative of sleep inertia, followed by improvements lasting up to 155 minutes after the nap. CONCLUSIONS: These findings suggest that the 10-minute nap was overall the most effective afternoon nap duration of the nap lengths examined in this study. The implications from these results also suggest a need to consider a process occurring in the first 10 minutes of sleep that may account for the benefits associated with brief naps.
85Sleep Inertia in Aviation.PubMed
Fabien Sauvet, Vincent Beauchamps, Philippe Cabon
Aerosp Med Hum Perform. 2024 Apr 1;95(4):206-213. doi: 10.3357/AMHP.6343.2024.
Sleep inertia is the transition state during which alertness and cognitive performance are temporarily impaired after awakening. Magnitude and time course of sleep inertia are characterized by high individual variability with large differences between the cognitive functions affected. This period of impairment is of concern to pilots, who take sleep or nap periods during on-call work hours or in-flight rest, then need to perform safety-critical tasks soon after waking. This review analyzes literature related to sleep inertia and countermeasures applicable for aviation. The large part of scientific literature that focuses on sleep inertia is based on studies in patients with chronic sleep inertia. We analyzed 8 narrative reviews and 64 papers related to acute sleep inertia in healthy subjects. Sleep inertia is a multifactorial, complex process, and many different protocols have been conducted, with a low number of subjects, in noncontrolled laboratory designs, with questionnaires or cognitive tests that have not been replicated. Evidence suggests that waking after sleep loss, or from deeper stages of sleep, can exacerbate sleep inertia through complex interactions between awakening and sleep-promoting brain structures. Nevertheless, no meta-analyses are possible and extrapolation to pilots' performances is hypothetical. Studies in real life or simulated operational situations must be conducted to improve the description of the impact of sleep inertia and kinetics on pilots' performances. Taking rest or sleep time remains the main method for pilots to fight against fatigue and related decreases in performance. We propose proactive strategies to mitigate sleep inertia and improve alertness.
86Pharmacokinetic and pharmacodynamic responses to caffeine in poor and normal sleepers.PubMed
P Tiffin, H Ashton, R Marsh, et al.
Psychopharmacology (Berl). 1995 Oct;121(4):494-502. doi: 10.1007/BF02246500.
Pharmacokinetic and pharmacodynamic responses to caffeine (2.5 mg/kg) were compared between ten healthy self-rated poor sleepers and ten normal sleepers. Sleep pattern assessed by the Pittsburgh Sleep Quality Index (PSQI). There was no significant difference in mean estimated daily caffeine consumption between the groups. The poor sleepers had significantly higher scores for neuroticism on the Eysenck Personality Questionnaire (EPQ) and anxiety on the Hospital Anxiety Depression (HAD) scale, compared with normal sleepers. Caffeine pharmacokinetics were assessed by measurement of saliva caffeine concentrations. Poor sleepers showed significantly greater variability in caffeine Cmax, clearance had half-life, compared to normal sleepers. Pharmacodynamic measures included heart rate, blood pressure, visual analogue scales for concentration, vigilance and relaxation, psychomotor performance [Digit Symbol Substitution Test (DSST) and tapping rate (TR)] and EEG activity [Contingent negative variation (CNV), auditory evoked potential and power spectral analysis]. Prior to caffeine administration, poor sleepers compared to normal sleepers had faster heart rates, lower ratings for concentration and relaxation, poorer performance on the DSST, greater CNV magnitude, faster peak alpha frequency and lower delta, theta and beta power. These differences persisted after caffeine ingestion and overall differences between the groups on these measures were significant (P < 0.01-.001). Post-dose, but not pre-dose, scores for vigilance and TR were significantly lower overall in poor compared with normal sleepers. Despite the baseline differences between poor and normal sleepers, the changes following caffeine administration were similar in direction and magnitude in both groups.
87Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial.PubMed
Carissa L Gardiner, Jonathon Weakley, Louise M Burke, et al.
Sleep. 2025 Apr 11;48(4). doi: 10.1093/sleep/zsae230.
STUDY OBJECTIVES: To investigate the effect of a typical dose of caffeine and a high dose of caffeine consumed in the morning, afternoon, and evening on subsequent sleep. METHODS: Using a placebo-controlled, double-blind, randomized crossover design, 23 males (25.3 ± 5.0 years) with a moderate habitual caffeine intake (<300 mg∙day-1) completed seven conditions: placebo, and 100 and 400 mg of caffeine consumed 12, 8, and 4 hours prior to bedtime, with a 48-hour washout. In-home partial polysomnography and sleep diaries were used to assess sleep. Linear mixed models estimated the effect of each condition. RESULTS: No significant effect on objective or subjective sleep occurred with the 100 mg dose of caffeine compared with the placebo (p > .05), but significant effects occurred with the 400 mg dose (p < .05). Significant delays in sleep initiation and alterations to sleep architecture were observed when 400 mg was consumed within 12 hours of bedtime (p < .05), and significantly greater sleep fragmentation occurred when 400 mg was consumed within 8 hours of bedtime (p < .05). Additionally, perceived sleep quality was significantly reduced when 400 mg was consumed 4 hours prior to bedtime (-34.02%, p = .006) but not at 8 or 12 hours. CONCLUSIONS: A 100 mg dose of caffeine can be consumed up to 4 hours prior to bedtime, but 400 mg may negatively impact sleep when consumed as one dose within 12 hours of bedtime, with the adverse influence on sleep increasing the closer consumption occurs to bedtime. The discrepancy between objective and subjective sleep quality suggests that individuals may have difficulty accurately perceiving the influence of caffeine on sleep quality. CLINICAL TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, registration number: ACTRN12621001625864, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12621001625864.
88Effects of caffeine on skin and core temperatures, alertness, and recovery sleep during circadian misalignment.PubMed
Andrew W McHill, Benjamin J Smith, Kenneth P Wright
J Biol Rhythms. 2014 Apr;29(2):131-43. doi: 10.1177/0748730414523078.
Caffeine promotes wakefulness during night shift work, although it also disturbs subsequent daytime sleep. Increased alertness by caffeine is associated with a higher core body temperature (CBT). A lower CBT and a narrow distal-to-proximal skin temperature gradient (DPG) have been reported to be associated with improved sleep, yet whether caffeine influences the DPG is unknown. We tested the hypothesis that the use caffeine during nighttime total sleep deprivation would reduce the DPG, increase CBT and alertness, and disturb subsequent daytime recovery sleep. We also expected that a greater widening of the DPG prior to sleep would be associated with a greater degree of sleep disturbance. Thirty healthy adults (9 females) aged 21.6 ± 3.5 years participated in a double-blind, 28-h modified constant routine protocol. At 23 h of wakefulness, participants in the treatment condition (n = 10) were given 2.9 mg/kg caffeine, equivalent to ~200 mg (or 2 espressos) for a 70-kg adult, 5 h before a daytime recovery sleep episode. Throughout the protocol, core and skin body temperatures, DPG, sleep architecture, and subjective alertness and mood were measured. Prior to sleep, caffeine significantly widened the DPG and increased CBT, alertness, and clear-headedness (p < 0.05). Caffeine also disturbed daytime recovery sleep (p < 0.05). Increased CBT and a wider DPG prior to sleep were associated with a longer latency to sleep, and a wider DPG was associated with disturbed recovery sleep (i.e., increased wakefulness after sleep onset, increased stage 1 sleep, decreased sleep efficiency, and decreased slow wave sleep) (p < 0.05). A widening of the DPG following nighttime caffeine may represent a component of the integrated physiological response by which caffeine improves alertness and disturbs subsequent daytime recovery sleep. Furthermore, our findings highlight that sleep disturbances associated with caffeine consumed near the circadian trough of alertness are still present when daytime recovery sleep occurs 5 h or approximately 1 half-life later.
89Caffeine Use and Associations With Sleep in Adolescents With and Without ADHD.PubMed
Caroline N Cusick, Joshua M Langberg, Rosanna Breaux, et al.
J Pediatr Psychol. 2020 Jul 1;45(6):643-653. doi: 10.1093/jpepsy/jsaa033.
OBJECTIVE: The objective of this study was to compare caffeine consumption in the morning, afternoon, and evening in adolescents with and without attention-deficit/hyperactivity disorder (ADHD) and examine associations with sleep functioning. METHODS: Participants were 302 adolescents (ages 12-14) with (N = 140) and without (N = 162) ADHD. Adolescents wore actigraph watches to assess total sleep time and wake after sleep onset and reported on sleep-wake problems and the number of caffeinated beverages consumed per day in the morning, afternoon, and evening. Parents reported on adolescents' difficulties initiating and maintaining sleep. Chi-square tests, odds ratios, and path analyses were conducted. RESULTS: Analyses controlled for sex, medication status, and pubertal development. Adolescents with ADHD were 2.47 times more likely to consume caffeine in the afternoon and evening than adolescents without ADHD. Path analyses indicated significant associations between afternoon caffeine use and more self-reported sleep problems for adolescents with and without ADHD, and an association between evening caffeine use and self-reported sleep problems only in adolescents with ADHD. Afternoon caffeine use was associated with parent-reported sleep problems in adolescents with ADHD only. Caffeine use was not associated with actigraphy-assessed sleep. CONCLUSION: This is the first study to show that adolescents with ADHD consume more caffeine than peers during later times of the day. Additionally, caffeine use is more consistently associated with poorer subjective sleep functioning in adolescents with ADHD. Pediatricians and mental health professionals should assess for caffeine use in adolescents with ADHD and co-occurring sleep problems.
90Circadian regulation of glucose, lipid, and energy metabolism in humans.PubMed
Eleonora Poggiogalle, Humaira Jamshed, Courtney M Peterson
Metabolism. 2018 Jul;84:11-27. doi: 10.1016/j.metabol.2017.11.017. Epub 2018 Jan 9.
The circadian system orchestrates metabolism in daily 24-hour cycles. Such rhythms organize metabolism by temporally separating opposing metabolic processes and by anticipating recurring feeding-fasting cycles to increase metabolic efficiency. Although animal studies demonstrate that the circadian system plays a pervasive role in regulating metabolism, it is unclear how, and to what degree, circadian research in rodents translates into humans. Here, we review evidence that the circadian system regulates glucose, lipid, and energy metabolism in humans. Using a range of experimental protocols, studies in humans report circadian rhythms in glucose, insulin, glucose tolerance, lipid levels, energy expenditure, and appetite. Several of these rhythms peak in the biological morning or around noon, implicating earlier in the daytime is optimal for food intake. Importantly, disruptions in these rhythms impair metabolism and influence the pathogenesis of metabolic diseases. We therefore also review evidence that circadian misalignment induced by mistimed light exposure, sleep, or food intake adversely affects metabolic health in humans. These interconnections among the circadian system, metabolism, and behavior underscore the importance of chronobiology for preventing and treating type 2 diabetes, obesity, and hyperlipidemia.
91The Sleep of the Ring: Comparison of the ŌURA Sleep Tracker Against Polysomnography.PubMed
Massimiliano de Zambotti, Leonardo Rosas, Ian M Colrain, et al.
Behav Sleep Med. 2019 Mar-Apr;17(2):124-136. doi: 10.1080/15402002.2017.1300587. Epub 2017 Mar 21.
: To evaluate the performance of a multisensor sleep-tracker (ŌURA ring) against polysomnography (PSG) in measuring sleep and sleep stages. : Forty-one healthy adolescents and young adults (13 females; Age: 17.2 ± 2.4 years). : Sleep data were recorded using the ŌURA ring and standard PSG on a single laboratory overnight. Metrics were compared using Bland-Altman plots and epoch-by-epoch (EBE) analysis. : Summary variables for sleep onset latency (SOL), total sleep time (TST), and wake after sleep onset (WASO) were not different between ŌURA ring and PSG. PSG-ŌURA discrepancies for WASO were greater in participants with more PSG-defined WASO ( < .001). Compared with PSG, ŌURA ring underestimated PSG N3 (~20 min) and overestimated PSG REM (~17 min; < .05). PSG-ŌURA differences for TST and WASO lay within the ≤ 30 min a-priori-set clinically satisfactory ranges for 87.8% and 85.4% of the sample, respectively. From EBE analysis, ŌURA ring had a 96% sensitivity to detect sleep, and agreement of 65%, 51%, and 61%, in detecting "light sleep" (N1), "deep sleep" (N2 + N3), and REM sleep, respectively. Specificity in detecting wake was 48%. Similarly to PSG-N3 ( < .001), "deep sleep" detected with the ŌURA ring was negatively correlated with advancing age ( = .001). ŌURA ring correctly categorized 90.9%, 81.3%, and 92.9% into PSG-defined TST ranges of < 6 hr, 6-7 hr, > 7 hr, respectively. : Multisensor sleep trackers, such as the ŌURA ring have the potential for detecting outcomes beyond binary sleep-wake using sources of information in addition to motion. While these first results could be viewed as promising, future development and validation are needed.
92Performance of consumer wrist-worn sleep tracking devices compared to polysomnography: a meta-analysis.PubMed
Young Jeong Lee, Jae Yong Lee, Jae Hoon Cho, et al.
J Clin Sleep Med. 2025 Mar 1;21(3):573-582. doi: 10.5664/jcsm.11460.
STUDY OBJECTIVES: The use of sleep tracking devices is increasing as people become more aware of the importance of sleep and interested in monitoring their patterns. With many devices on the market, we conducted a meta-analysis comparing sleep scoring data from consumer wrist-worn sleep tracking devices with polysomnography to validate the accuracy of these devices. METHODS: We retrieved studies from the databases of SCOPUS, EMBASE, Cochrane Library, PubMed, Web of Science, and KoreaMed and OVID Medline up to March 2024. We compared personal data about participants and information on objective sleep parameters. RESULTS: From 24 studies, data of 798 patient using Fitbit, Jawbone, myCadian watch, WHOOP strap, Garmin, Basis B1, Zulu Watch, Huami Arc, E4 wristband, Fatigue Science Readiband, Apple Watch, or Xiaomi Mi Band 5 were analyzed. There were significant differences in total sleep time (mean difference, -16.854; 95% confidence interval, [-26.332; -7.375]), sleep efficiency (mean difference, -4.691; 95% confidence interval, [-7.079; -2.302]), sleep latency (mean difference, 2.574; 95% confidence interval, [0.606; 4.542]), and wake after sleep onset (mean difference, 13.255; 95% confidence interval, [4.522; 21.988]) between all consumer sleep tracking devices and polysomnography. In subgroup analysis, there was no significant difference in wake after sleep onset between Fitbit and polysomnography. There was also no significant difference in sleep latency between other devices and polysomnography. Fitbit measured sleep latency longer than other devices, and other devices measured wake after sleep onset longer. Based on Begg and Egger's test, there was no publication bias in total sleep time and sleep efficiency. CONCLUSIONS: Wrist-worn sleep tracking devices, although popular, are not as reliable as polysomnography in measuring key sleep parameters such as total sleep time, sleep efficiency, and sleep latency. Physicians and consumers should be aware of their limitations and interpret results carefully, though they can still be useful for tracking general sleep patterns. Further improvements and clinical studies are needed to enhance their accuracy. CITATION: Lee YJ, Lee JY, Cho JH, Kang YJ, Choi JH. Performance of consumer wrist-worn sleep tracking devices compared to polysomnography: a meta-analysis. 2025;21(3):573-582.
93Concordance of polysomnographic and actigraphic measurement of sleep and wake in older women with insomnia.PubMed
Diana M Taibi, Carol A Landis, Michael V Vitiello
J Clin Sleep Med. 2013 Mar 15;9(3):217-25. doi: 10.5664/jcsm.2482.
STUDY OBJECTIVES: The objective of this secondary analysis was to evaluate concurrent validity of actigraphy and polysomnography (PSG) in older women with insomnia. METHODS: Concurrent validity of actigraphy and PSG was examined through (1) comparison of sleep outcomes from each recording method; (2) calculation of sensitivity, specificity, accuracy, and predictive values from epoch-by-epoch data; and (3) statistical and graphical exploration of the relationship between sleep disturbance severity and concordance of actigraphy and PSG. Subjects were 16 community-dwelling older women (mean age 69.4 ± 8.1) with insomnia who underwent 8 nights of concurrent actigraphy and PSG. RESULTS: Sleep efficiency reflected much greater sleep disturbance on PSG (66.9%) than actigraphy (84.4%). Based on generalized linear models, the parameter estimates for agreement between actigraphy and PSG were statistically significant (p < 0.05) for total sleep time and sleep latency, verged on significance for WASO (p = 0.052), but was not significant for sleep efficiency (p = 0.20). Epoch-by-epoch analysis showed high sensitivity (96.1%), low specificity (36.4%), and modest values on agreement (75.4%) and predictive values of sleep (74.7%) and wake (80.2%). Generalized linear models showed that overall accuracy of actigraphy declined as sleep efficiency declined (unstandardized Beta = 0.741, p < 0.001). Based on this model, sleep efficiency of 73% was the point at which accuracy declined below an acceptable accuracy value of 80%. CONCLUSIONS: Actigraphy offers a relatively inexpensive and unobtrusive method for measuring sleep, but it appears to underestimate sleep disturbance, particularly at sleep efficiency levels below 73%, in older women with insomnia.
94Wearable Sleep Technology in Clinical and Research Settings.PubMed
Massimiliano de Zambotti, Nicola Cellini, Aimée Goldstone, et al.
Med Sci Sports Exerc. 2019 Jul;51(7):1538-1557. doi: 10.1249/MSS.0000000000001947.
: The accurate assessment of sleep is critical to better understand and evaluate its role in health and disease. The boom in wearable technology is part of the digital health revolution and is producing many novel, highly sophisticated and relatively inexpensive consumer devices collecting data from multiple sensors and claiming to extract information about users' behaviors, including sleep. These devices are now able to capture different biosignals for determining, for example, HR and its variability, skin conductance, and temperature, in addition to activity. They perform 24/7, generating overwhelmingly large data sets (big data), with the potential of offering an unprecedented window on users' health. Unfortunately, little guidance exists within and outside the scientific sleep community for their use, leading to confusion and controversy about their validity and application. The current state-of-the-art review aims to highlight use, validation and utility of consumer wearable sleep-trackers in clinical practice and research. Guidelines for a standardized assessment of device performance is deemed necessary, and several critical factors (proprietary algorithms, device malfunction, firmware updates) need to be considered before using these devices in clinical and sleep research protocols. Ultimately, wearable sleep technology holds promise for advancing understanding of sleep health; however, a careful path forward needs to be navigated, understanding the benefits and pitfalls of this technology as applied in sleep research and clinical sleep medicine.
95Smartphone apps for snoring.PubMed
M Camacho, M Robertson, J Abdullatif, et al.
J Laryngol Otol. 2015 Oct;129(10):974-9. doi: 10.1017/S0022215115001978. Epub 2015 Sep 3.
OBJECTIVE: To identify and systematically evaluate user-friendly smartphone snoring apps. METHODS: The Apple iTunes app store was searched for snoring apps that allow recording and playback. Snoring apps were downloaded, evaluated and rated independently by four authors. Two patients underwent polysomnography, and the data were compared with simultaneous snoring app recordings, and one patient used the snoring app at home. RESULTS: Of 126 snoring apps, 13 met the inclusion and exclusion criteria. The most critical app feature was the ability to graphically display the snoring events. The Quit Snoring app received the highest overall rating. When this app's recordings were compared with in-laboratory polysomnography data, app snoring sensitivities ranged from 64 to 96 per cent, and snoring positive predictive values ranged from 93 to 96 per cent. A chronic snorer used the app nightly for one month and tracked medical interventions. Snoring decreased from 200 to 10 snores per hour, and bed partner snoring complaint scores decreased from 9 to 2 (on a 0-10 scale). CONCLUSION: Select smartphone apps are user-friendly for recording and playing back snoring sounds. Preliminary comparison of more than 1500 individual snores demonstrates the potential clinical utility of such apps; however, further validation testing is recommended.
96The mobile sleep lab app: An open-source framework for mobile sleep assessment based on consumer-grade wearable devices.PubMed
Andreas Burgdorf, Inga Güthe, Marko Jovanović, et al.
Comput Biol Med. 2018 Dec 1;103:8-16. doi: 10.1016/j.compbiomed.2018.09.025. Epub 2018 Oct 6.
BACKGROUND: Sleep disorders have a prevalence of up to 50% and are commonly diagnosed using polysomnography. However, polysomnography requires trained staff and specific equipment in a laboratory setting, which are expensive and limited resources are available. Mobile and wearable devices such as fitness wristbands can perform limited sleep monitoring but are not evaluated well. Here, the development and evaluation of a mobile application to record and synchronize data from consumer-grade sensors suitable for sleep monitoring is presented and evaluated for data collection capability in a clinical trial. METHODS: Wearable and ambient consumer-grade sensors were selected to mimic the functionalities of clinical sleep laboratories. Then, a modular application was developed for recording, processing and visualizing the sensor data. A validation was performed in three phases: (1) sensor functionalities were evaluated, (2) self-experiments were performed in full-night experiments, and (3) the application was tested for usability in a clinical trial on primary snoring. RESULTS: The evaluation of the sensors indicated their suitability for assessing basic sleep characteristics. Additionally, the application successfully recorded full-night sleep. The collected data was of sufficient quality to detect and measure body movements, cardiac activity, snoring and brightness. The ongoing clinical trial phase showed the successful deployment of the application by medical professionals. CONCLUSION: The proposed software demonstrated a strong potential for medical usage. With low costs, it can be proposed for screening, long-term monitoring or in resource-austere environments. However, further validations are needed, in particular the comparison to a clinical sleep laboratory.
97Association Between Slow-Wave Sleep Loss and Incident Dementia.PubMed
Jayandra J Himali, Andree-Ann Baril, Marina G Cavuoto, et al.
JAMA Neurol. 2023 Dec 1;80(12):1326-1333. doi: 10.1001/jamaneurol.2023.3889.
IMPORTANCE: Slow-wave sleep (SWS) supports the aging brain in many ways, including facilitating the glymphatic clearance of proteins that aggregate in Alzheimer disease. However, the role of SWS in the development of dementia remains equivocal. OBJECTIVE: To determine whether SWS loss with aging is associated with the risk of incident dementia and examine whether Alzheimer disease genetic risk or hippocampal volumes suggestive of early neurodegeneration were associated with SWS loss. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study included participants in the Framingham Heart Study who completed 2 overnight polysomnography (PSG) studies in the time periods 1995 to 1998 and 2001 to 2003. Additional criteria for individuals in this study sample were an age of 60 years or older and no dementia at the time of the second overnight PSG. Data analysis was performed from January 2020 to August 2023. EXPOSURE: Changes in SWS percentage measured across repeated overnight sleep studies over a mean of 5.2 years apart (range, 4.8-7.1 years). MAIN OUTCOME: Risk of incident all-cause dementia adjudicated over 17 years of follow-up from the second PSG. RESULTS: From the 868 Framingham Heart Study participants who returned for a second PSG, this cohort included 346 participants with a mean age of 69 years (range, 60-87 years); 179 (52%) were female. Aging was associated with SWS loss across repeated overnight sleep studies (mean [SD] change, -0.6 [1.5%] per year; P < .001). Over the next 17 years of follow-up, there were 52 cases of incident dementia. In Cox regression models adjusted for age, sex, cohort, positivity for at least 1 APOE ε4 allele, smoking status, sleeping medication use, antidepressant use, and anxiolytic use, each percentage decrease in SWS per year was associated with a 27% increase in the risk of dementia (hazard ratio, 1.27; 95% CI, 1.06-1.54; P = .01). SWS loss with aging was accelerated in the presence of Alzheimer disease genetic risk (ie, APOE ε4 allele) but not hippocampal volumes measured proximal to the first PSG. CONCLUSIONS AND RELEVANCE: This cohort study found that slow-wave sleep percentage declined with aging and Alzheimer disease genetic risk, with greater reductions associated with the risk of incident dementia. These findings suggest that SWS loss may be a modifiable dementia risk factor.
98Evaluating User Compliance in Mobile Health Apps: Insights from a 90-Day Study Using a Digital Sleep Diary.PubMed
Hlín Kristbergsdottir, Lisa Schmitz, Erna Sif Arnardottir, et al.
Diagnostics (Basel). 2023 Sep 8;13(18):2883. doi: 10.3390/diagnostics13182883.
UNLABELLED: Sleep diaries are the gold standard for subjective assessment of sleep variables in clinical practice. Digitization of sleep diaries is needed, as paper versions are prone to human error, memory bias, and difficulties monitoring compliance. METHODS: 45 healthy eligible participants (M = 50.3 years, range 23-74, 56% female) were asked to use a sleep diary mobile app for 90 consecutive days. Univariate and bivariate analysis was used for group comparison and linear regression for analyzing reporting trends and compliance over time. RESULTS: Overall compliance was high in the first two study months but tended to decrease over time ( < 0.001). Morning and evening diary entries were highly correlated (r = 0.932, < 0.001) and participants significantly answered on average 4.1 days (95% CI [1.7, 6.6]) more often in the morning (M = 60.2, sd = 22.1) than evening ((M = 56.1, sd = 22.2), < 0.001). CONCLUSION: Using a daily diary assessment in a longitudinal sleep study with a sleep diary delivered through a mobile application was feasible, and compliance in this study was satisfactory.
99Relationship of sleep with diurnal cortisol rhythm considering sleep measurement and cortisol sampling schemes.PubMed
Kaige Guo, Xiaolin Zhao, Jiahao Luo, et al.
Psychoneuroendocrinology. 2024 Apr;162:106952. doi: 10.1016/j.psyneuen.2023.106952. Epub 2024 Jan 3.
Information on the relationships between the previous night's sleep and the next-day diurnal cortisol rhythm is inconsistent due to confounding factors such as sleep measurements (trait/state sleep and objective/subjective sleep) and cortisol sampling schemes. Therefore, this study aimed to investigate these relationships, considering the confounding factors. College students (n = 79) wore actigraphy for 3 days to undergo an evaluation of previous night-time sleep objectively and reported their subjective sleep parameters in a sleep diary. In addition, participants provided six salivary cortisol samples daily. Furthermore, six cortisol sampling schemes were created to reflect diurnal cortisol rhythms, and two different methods were used to calculate the index of diurnal cortisol slope (DCS). A multilevel model was created to examine the impact of both trait and state sleep on next-day diurnal cortisol rhythm. The results revealed that higher objective state sleep efficiency and longer objective state total sleep time were associated with a higher cortisol awakening response (CAR). Moreover, higher objective trait sleep efficiency and longer objective trait total sleep time were associated with higher waking cortisol levels and steeper DCS. In addition, a minimum of four saliva samples were required at different time points, including upon waking, 30 min after waking, 1 h after waking, and at bedtime, to explore the relationship of sleep efficiency/total sleep time with waking cortisol, CAR, and DCS. Furthermore, the index of the peak-to-bed slope was appropriately employed to examine the relationship between sleep efficiency and DCS, whereas the wake-to-bed slope was effective for examining the relationship between total sleep time and DCS. In summary, this study clarified the relationship between sleep and next-day diurnal cortisol rhythm and suggested a cost-effective cortisol sampling schedule and calculation methods.
100Lifestyle Mindfulness In Clinical PracticePubMed
Ranya A. Srour, Daniel Keyes
Mindfulness is a self-regulated state of non-judgemental and purposeful awareness of the present moment. Psychotherapy pioneer Jon Kabat-Zinn developed the mindfulness-based stress reduction (MBSR) protocol for the self-regulation of chronic pain and stress through meditation and mindfulness. In preliminary studies, Kabat-Zinn describes how meditation facilitates a state of detached observation by redirecting attention toward proprioception. This "uncouples" the sensory component of pain from the affective or emotional element, thus reducing suffering through cognitive reappraisal. Individuals can reinterpret and reframe their thoughts through cognitive reappraisal, reducing stress and suffering. Studies report strong adherence and long-term positive effects of MBSR on stress, depression, anxiety, and pain following the training period, with benefits lasting for several years. A pivotal study on mindfulness and the brain demonstrated that a brief MBSR program increased left-sided anterior activity correlated with positive affect. More recent research further supports this finding, indicating that mindfulness meditation reduces stress and enhances the activation of brain regions linked to mood regulation and attention control. Specifically, it is suggested that MBSR improves the activation of the brain's anterior cingulate cortex, an executive attention center. These findings highlight how mindfulness strengthens neuronal networks, cultivating self-awareness, emotional regulation, and adaptive stress responses. Furthermore, mindfulness may strengthen the mind-body connection, enabling individuals to effectively self-regulate symptoms of pain, anxiety, depression, and stress. Mindfulness aims to liberate the self from physical and psychological suffering while cultivating the necessary skills to manage stressful situations. It is emphasized that mindfulness is not a quick fix but a long-term intervention that requires dedicated practice and an intentional way of living. Stress is a fundamental and necessary part of life. Stress is not exclusive to negative experiences and may result from any form of stimulation, including positive experiences. Cortisol, the stress hormone, is produced during negative and positive experiences and is crucial in promoting alertness, focus, and energy. It allows us to get up in the morning and maintain energy throughout the day. However, prolonged or excessive stress can have detrimental effects on our health. High cortisol levels over an extended period can disrupt sleep patterns, impair cognitive function, weaken the immune system, and contribute to various health problems. Therefore, while stress is essential in moderate amounts, it is crucial to manage excessive stress to maintain a healthy lifestyle. The body's response to stressors can be observed through physiological and behavioral changes controlled by biological processes. Recent research supports the theory that the hypothalamic-pituitary-adrenal (HPA) axis regulates the stress response. Activation of the HPA axis begins through an initial exposure to a stressor. The activation of the HPA axis has neuronal origins regulated by the paraventricular nucleus of the hippocampus, which releases corticotropin-releasing factors. The HPA axis then releases glucocorticoids, stimulating the body's physical response to stress. Glucocorticoids and other cortical hormones are major regulators of the HPA axis and normally produce a healthy, adaptive stress response. However, chronic stress results in excessive or prolonged activation of the HPA axis, leading to dysregulation and a maladaptive stress response. A wide body of evidence supports using a mind-body approach to regulate the HPA axis and address psychophysiological stress. Non-pharmacological behavioral interventions like MBSR have been shown to effectively regulate exaggerated or problematic stress responses through breathing exercises, meditation, and mindfulness (see . MSBR and Stress). Behavioral interventions like MBSR aim not to remove stress but to manage it effectively and completely.
101Stress, cortisol and suicide risk.PubMed
Daryl B O'Connor, Nicola Gartland, Rory C O'Connor
Int Rev Neurobiol. 2020;152:101-130. doi: 10.1016/bs.irn.2019.11.006. Epub 2020 Jan 27.
Suicide is a global health issue accounting for at least 800,000 deaths per annum. Numerous models have been proposed that differ in their emphasis on the role of psychological, social, psychiatric and neurobiological factors in explaining suicide risk. Central to many models is a stress-diathesis component which states that suicidal behavior is the result of an interaction between acutely stressful events and a susceptibility to suicidal behavior (a diathesis). This article presents an overview of studies that demonstrate that stress and dysregulated hypothalamic-pituitary-adrenal (HPA) axis activity, as measured by cortisol levels, are important additional risk factors for suicide. Evidence for other putative stress-related suicide risk factors including childhood trauma, impaired executive function, impulsivity and disrupted sleep are considered together with the impact of family history of suicide, perinatal and epigenetic influences on suicide risk.
102Overnight therapy? The role of sleep in emotional brain processing.PubMed
Matthew P Walker, Els van der Helm
Psychol Bull. 2009 Sep;135(5):731-48. doi: 10.1037/a0016570.
Cognitive neuroscience continues to build meaningful connections between affective behavior and human brain function. Within the biological sciences, a similar renaissance has taken place, focusing on the role of sleep in various neurocognitive processes and, most recently, on the interaction between sleep and emotional regulation. This review surveys an array of diverse findings across basic and clinical research domains, resulting in a convergent view of sleep-dependent emotional brain processing. On the basis of the unique neurobiology of sleep, the authors outline a model describing the overnight modulation of affective neural systems and the (re)processing of recent emotional experiences, both of which appear to redress the appropriate next-day reactivity of limbic and associated autonomic networks. Furthermore, a rapid eye movement (REM) sleep hypothesis of emotional-memory processing is proposed, the implications of which may provide brain-based insights into the association between sleep abnormalities and the initiation and maintenance of mood disturbances.
103Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials.PubMed
Alexander J Scott, Thomas L Webb, Marrissa Martyn-St James, et al.
Sleep Med Rev. 2021 Dec;60:101556. doi: 10.1016/j.smrv.2021.101556. Epub 2021 Sep 23.
The extent to which sleep is causally related to mental health is unclear. One way to test the causal link is to evaluate the extent to which interventions that improve sleep quality also improve mental health. We conducted a meta-analysis of randomised controlled trials that reported the effects of an intervention that improved sleep on composite mental health, as well as on seven specific mental health difficulties. 65 trials comprising 72 interventions and N = 8608 participants were included. Improving sleep led to a significant medium-sized effect on composite mental health (g+ = -0.53), depression (g+ = -0.63), anxiety (g+ = -0.51), and rumination (g+ = -0.49), as well as significant small-to-medium sized effects on stress (g+ = -0.42), and finally small significant effects on positive psychosis symptoms (g+ = -0.26). We also found a dose response relationship, in that greater improvements in sleep quality led to greater improvements in mental health. Our findings suggest that sleep is causally related to the experience of mental health difficulties. Future research might consider how interventions that improve sleep could be incorporated into mental health services, as well as the mechanisms of action that explain how sleep exerts an effect on mental health.
104Sleep quality: An evolutionary concept analysis.PubMed
Kathy L Nelson, Jean E Davis, Cynthia F Corbett
Nurs Forum. 2022 Jan;57(1):144-151. doi: 10.1111/nuf.12659. Epub 2021 Oct 5.
AIM: To clarify the meaning of the concept sleep quality. BACKGROUND: Sleep loss and sleep quality are global health concerns. Poor sleep quality has significant adverse health outcomes. A clarification of the term is necessary to inform patients and healthcare providers, promote consistent theoretical and operational definitions in research, and develop prevention and treatment strategies. DESIGN: Concept analysis. DATA SOURCES: Scientific literature from electronic databases (CINAHL, PsycINFO, PubMED, Web of Science, and JSTOR) and definitions from online dictionaries. REVIEW METHODS: Rodgers' Evolutionary method was applied to guide the concept analysis to identify and determine the attributes, antecedents, and consequences. RESULTS: Sleep quality is defined as an individual's self-satisfaction with all aspects of the sleep experience. Sleep quality has four attributes: sleep efficiency, sleep latency, sleep duration, and wake after sleep onset. Antecedents include physiological (e.g., age, circadian rhythm, body mass index, NREM, REM), psychological (e.g., stress, anxiety, depression), and environmental factors (e.g., room temperature, television/device use), and family/social commitments. Good sleep quality has positive effects such as feeling rested, normal reflexes, and positive relationships. Poor sleep quality consequences include fatigue, irritability, daytime dysfunction, slowed responses, and increased caffeine/alcohol intake. CONCLUSIONS: Sleep quality is essential, and poor sleep quality contributes to disease and poor health outcomes. Given the extensive consequences of poor sleep quality, nurses and clinicians are vital in instructing the importance of good sleep.
105Effects of Sleep Deprivation on Physical and Mental Health Outcomes: An Umbrella Review.PubMed
Arambh Sanjay Shah, Mitresh Raj Pant, Tulasiram Bommasamudram, et al.
Am J Lifestyle Med. 2025 May 27:15598276251346752. doi: 10.1177/15598276251346752.
The increasing prevalence of reduced habitual sleep duration presents a significant public health challenge, impacting cardiovascular health, metabolic function and mental well-being. This umbrella review analyses findings from systematic reviews and meta-analyses to comprehensively evaluate the consequences of sleep deprivation (SD) on health. The databases searched included PubMed, Scopus, and Web of Science. Inclusion criteria focused on adult populations with SD and systematic reviews/meta-analyses. Twenty-nine articles were included in the final synthesis, encompassing a variety of health outcomes. Key findings highlight a U-shaped relationship between sleep duration and all-cause mortality, with both short (<7 h) sleep durations associated with increased risks. SD was a significant risk factor for cardiovascular diseases such as hypertension, stroke and coronary heart disease. Alongside heightened risks of metabolic disorders, like obesity and type 2 diabetes. Moreover, SD contributed to elevated anxiety levels, impaired emotional regulation. As well as increased susceptibility to stress and depressive symptoms. This synthesis underscores the critical importance of maintaining recommended sleep duration (typically 7-9 h for adults) to mitigate these health risks effectively. The findings support the need for robust public health interventions aimed at promoting healthy sleep habits to reduce the burden of associated health conditions and enhance overall well-being.
106Smartphone addiction, sleep quality, depression, anxiety, and stress among medical students.PubMed
Aleksandra Nikolic, Bojana Bukurov, Ilija Kocic, et al.
Front Public Health. 2023 Sep 6;11:1252371. doi: 10.3389/fpubh.2023.1252371. eCollection 2023.
INTRODUCTION: Studies consistently link excessive smartphone use to poor sleep quality, depression, anxiety, and stress. This study specifically aimed to investigate these associations among medical students in Belgrade and Nis (Central Serbia). MATERIALS AND METHODS: The cross-sectional study included a sample of 761 students, who were selected from both the Faculties of Medicine at the University of Belgrade and the University of Nis. Questionnaires, including the International Physical Activity Questionnaire - Short Form (IPAQ-SF), Smartphone Addiction Scale - Short Version (SAS-SV), the Pittsburgh Sleep Quality Index (PSQI), and the Depression, Anxiety, and Stress Scale - 21 items (DASS-21), were completed by the participants. Statistical analysis techniques, such as the Chi-square test, student's -test, and logistic regression, were employed to examine the relationship between smartphone addiction, physical activity, sleep quality, depression, anxiety, and stress. RESULTS: The findings indicated a prevalence of smartphone addiction among medical students at 21.7%, with rates of 22.9% among males and 21.1% among females. Females exhibited significantly higher scores on the SAS-SV scale compared to males ( = 0.032). Univariate logistic regression analysis revealed significant associations between smartphone addiction and spending over 4 h daily on smartphones (OR = 2.39; < 0.001), poor sleep quality (OR = 1.65; = 0,005), as well as elevated levels of stress (OR = 1.75; = 0.003), anxiety (OR = 2.04; < 0.001), and depression (OR = 2.29; < 0.001). Multivariate regression analysis identified spending more than 4 h daily on smartphones (OR = 2.39; < 0.001) and increased levels of depression (OR = 2.51; < 0.001) as independent significant factors associated with smartphone addiction. CONCLUSION: This study sheds light on the prevalence of smartphone addiction among medical students, with spending excessive time on smartphones and higher levels of depression standing out as significant factors. Future research should delve into the underlying mechanisms and causal relationships between smartphone addiction and these psychosocial factors. Understanding these connections will aid in developing effective interventions and strategies to tackle this growing public health concern.
107Effect of Yoga Breathing (Pranayama) on Exercise Tolerance in Patients with Chronic Obstructive Pulmonary Disease: A Randomized, Controlled Trial.PubMed
David A Kaminsky, Kalpalatha K Guntupalli, Joan Lippmann, et al.
J Altern Complement Med. 2017 Sep;23(9):696-704. doi: 10.1089/acm.2017.0102. Epub 2017 Jul 17.
OBJECTIVE: Pulmonary rehabilitation improves exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). However, many patients do not have access to pulmonary rehabilitation programs. We hypothesized that an alternative to pulmonary rehabilitation to improve exercise tolerance is the practice of pranayama, or yoga breathing, which could be done independently at home. We also sought to determine whether yoga nonprofessionals could adequately teach pranayama to patients. DESIGN: Proof-of-concept, randomized, double-blind, controlled pilot trial. SETTINGS/LOCATION: Two academic pulmonary practices. SUBJECTS: Forty-three patients with symptomatic, moderate-to-severe COPD. INTERVENTIONS: Twelve weeks of pranayama plus education versus education alone. Two yoga professionals trained the research coordinators to conduct all pranayama teaching and monitored the quality of the teaching and the practice of pranayama by study participants. OUTCOME MEASURES: The primary outcome was a change in the 6-min walk distance (6MWD). Secondary outcomes included changes in lung function, markers of oxidative stress and systemic inflammation, and measures of dyspnea and quality of life. RESULTS: The 6MWD increased in the pranayama group (least square mean [95% confidence interval] = 28 m [-5 to 61]) and decreased in the control group (-15 m [-47 to 16]), with a nearly significant treatment effect (p = 0.06) in favor of pranayama. Pranayama also resulted in small improvements in inspiratory capacity and air trapping. Both groups had significant improvements in various measures of symptoms, but no overall differences in respiratory system impedance or markers of oxidative stress or systemic inflammation. CONCLUSION: This pilot study successfully demonstrated that pranayama was associated with improved exercise tolerance in patients with COPD. Lay personnel were able to adequately teach patients to practice pranayama. These results suggest that pranayama may have significant clinical benefits for symptomatic patients with COPD, a concept that needs to be confirmed in future, larger clinical trials.
108A 14-week structured breathing program: an investigation into its impact on psychological health parameters in university students.PubMed
Alexandru Florian Crișan, Camelia Corina Pescaru, Adelina Maritescu, et al.
BMC Public Health. 2025 Apr 14;25(1):1395. doi: 10.1186/s12889-025-22585-8.
BACKGROUND: University students are prone to high levels of stress, anxiety, and sleep disturbances, which can negatively affect their mental health and academic performance. Breathing exercises have been suggested as a simple and effective intervention to reduce these issues. This study aimed to evaluate the impact of a 14-week structured breathing exercises program on the psychological well-being of physical therapy students, focusing on subjective happiness, sleep quality, worry levels, and emotional regulation. METHODS: This was a non-randomized study that included 46 s-year students. The intervention group received weekly 30-minute sessions of breathing exercises for 14 weeks, while the control group continued their usual activities. Data were collected at baseline and 14 weeks using validated questionnaires such as Oxford Happiness Questionnaire, Penn State Worry Questionnaire (PSWQ), positive and Negative Affect Schedule (PANAS), and Pittsburgh Sleep Quality Index (PSQI). Statistical analysis included paired samples t-tests and Wilcoxon singed-rank test. RESULTS: The intervention group demonstrated significant improvements in subjective happiness (p < 0.0001), positive affect (p < 0.0001), and sleep quality (p = 0.0001) post-intervention. A significant decrease was observed in worry levels (p = 0.0001), and negative affect was modestly reduced (p = 0.02). The control group showed no significant changes except for a minor increase in subjective happiness (p = 0.04). CONCLUSION: The 14-week structured breathing program significantly enhanced subjective happiness, emotional regulation, and sleep quality, reducing worry levels among physical therapy students. The results could contribute to integrating these techniques into educational programs and developing accessible strategies to improve student well-being. TRIAL REGISTRATION: The study was registered on clinicaltrials.gov on 09.05.2024 under the identification ID NCT06341569 ( https://clinicaltrials.gov/study/NCT06341569 ).
109Holistic Nursing in Practice: Mindfulness-Based Yoga as an Intervention to Manage Stress and Burnout.PubMed
Kelly Hilcove, Catherine Marceau, Prachi Thekdi, et al.
J Holist Nurs. 2021 Mar;39(1):29-42. doi: 10.1177/0898010120921587. Epub 2020 May 27.
PURPOSE: Effects of a mindfulness-based (MB) yoga practice on stress, burnout, and indicators of well-being among nurses and health care professionals (HCPs). DESIGN: A randomized controlled trial, 80 HCPs assigned to either MB yoga intervention or control group. METHOD: The MB yoga intervention group ( = 41) attended weekly yoga classes and practiced yoga independently. The control group ( = 39) did not receive the yoga intervention. Study participants completed pre- and postintervention questionnaires, instruments included (a) Perceived Stress Scale; (b) Maslach Burnout Inventory; (c) Vitality subscale of the Medical Outcomes Study Short Form-36; (d) Global Sleep Quality item, (e) Mindfulness Awareness Survey, and (f) subscale of the Brief Serenity Scale. Diurnal salivary cortisol and blood pressure were assessed pre and postintervention. RESULTS: Significant improvements ( < .01) noted in MB yoga compared with control for self-reported factors, including stress (Perceived Stress Scale), burnout (Maslach Burnout Inventory), vitality (Medical Outcomes Study Short Form-36), sleep (GSQ), serenity/inner haven (IH), and mindfulness (Mindfulness Awareness Survey). Diurnal cortisol slopes and blood pressure were not significantly improved. CONCLUSION: The MB yoga intervention had a statistically significant effect on the health and well-being of nurses and HCPs, most specifically for measures of stress; perceived stress, burnout, vitality, sleep quality, serenity, and mindfulness.